# Host/Target specific installation notes for GCC

Please read this document carefully before installing the GNU Compiler Collection on your machine.

- alpha*-*-*
- alpha*-dec-osf*
- alphaev5-cray-unicosmk*
- arc-*-elf
- arm-*-elf arm-*-coff arm-*-aout
- xscale-*-*
- avr
- c4x
- DOS
- dsp16xx
- *-*-freebsd*
- h8300-hms
- hppa*-hp-hpux*
- hppa*-hp-hpux10
- hppa*-hp-hpux11
- i370-*-*
- *-*-linux-gnu
- i?86-*-linux*aout
- i?86-*-linux*
- i?86-*-sco3.2v5*
- i?86-*-udk
- i?86-*-esix
- ia64-*-linux
- ia64-*-hpux*
- *-ibm-aix*
- ip2k-*-elf
- iq2000-*-elf
- m32r-*-elf
- m6811-elf
- m6812-elf
- m68k-hp-hpux
- mips-*-*
- mips-sgi-irix5
- mips-sgi-irix6
- powerpc*-*-* powerpc-*-sysv4
- powerpc-*-darwin*
- powerpc-*-elf powerpc-*-sysv4
- powerpc-*-linux-gnu*
- powerpc-*-netbsd*
- powerpc-*-eabiaix
- powerpc-*-eabisim
- powerpc-*-eabi
- powerpcle-*-elf powerpcle-*-sysv4
- powerpcle-*-eabisim
- powerpcle-*-eabi
- s390-*-linux*
- s390x-*-linux*
- s390x-ibm-tpf*
- *-*-solaris2*
- sparc-sun-solaris2*
- sparc-sun-solaris2.7
- sparc-*-linux*
- sparc64-*-solaris2*
- sparcv9-*-solaris2*
- *-*-sysv*
- vax-dec-ultrix
- *-*-vxworks*
- x86_64-*-* amd64-*-*
- xtensa-*-elf
- xtensa-*-linux*
- Microsoft Windows
- OS/2
- Older systems

- all ELF targets (SVR4, Solaris 2, etc.)

### alpha*-*-*

This section contains general configuration information for all alpha-based platforms using ELF (in particular, ignore this section for DEC OSF/1, Digital UNIX and Tru64 UNIX). In addition to reading this section, please read all other sections that match your target.

We require binutils 2.11.2 or newer. Previous binutils releases had a number of problems with DWARF 2 debugging information, not the least of which is incorrect linking of shared libraries.

### alpha*-dec-osf*

Systems using processors that implement the DEC Alpha architecture and are running the DEC/Compaq Unix (DEC OSF/1, Digital UNIX, or Compaq Tru64 UNIX) operating system, for example the DEC Alpha AXP systems.

As of GCC 3.2, versions before `alpha*-dec-osf4` are no longer supported. (These are the versions which identify themselves as DEC OSF/1.)

In Digital Unix V4.0, virtual memory exhausted bootstrap failures may be fixed by configuring with `--with-gc=simple`, reconfiguring Kernel Virtual Memory and Swap parameters per the `/usr/sbin/sys_check` Tuning Suggestions, or applying the patch in http://gcc.gnu.org/ml/gcc/2002-08/msg00822.html.

In Tru64 UNIX V5.1, Compaq introduced a new assembler that does not currently (2001-06-13) work with `mips-tfile`. As a workaround, we need to use the old assembler, invoked via the barely documented `-oldas` option. To bootstrap GCC, you either need to use the Compaq C Compiler:

            % CC=cc srcdir/configure [options] [target]

or you can use a copy of GCC 2.95.3 or higher built on Tru64 UNIX V4.0:

            % CC=gcc -Wa,-oldas srcdir/configure [options] [target]

As of GNU binutils 2.11.2, neither GNU `as` nor GNU `ld` are supported on Tru64 UNIX, so you must not configure GCC with `--with-gnu-as` or `--with-gnu-ld`.

GCC writes a `.verstamp` directive to the assembler output file unless it is built as a cross-compiler. It gets the version to use from the system header file `/usr/include/stamp.h`. If you install a new version of DEC Unix, you should rebuild GCC to pick up the new version stamp.

Note that since the Alpha is a 64-bit architecture, cross-compilers from 32-bit machines will not generate code as efficient as that generated when the compiler is running on a 64-bit machine because many optimizations that depend on being able to represent a word on the target in an integral value on the host cannot be performed. Building cross-compilers on the Alpha for 32-bit machines has only been tested in a few cases and may not work properly.

`make compare` may fail on old versions of DEC Unix unless you add `-save-temps` to `CFLAGS`. On these systems, the name of the assembler input file is stored in the object file, and that makes comparison fail if it differs between the `stage1` and `stage2` compilations. The option `-save-temps` forces a fixed name to be used for the assembler input file, instead of a randomly chosen name in `/tmp`. Do not add `-save-temps` unless the comparisons fail without that option. If you add `-save-temps`, you will have to manually delete the `.i` and `.s` files after each series of compilations.

GCC now supports both the native (ECOFF) debugging format used by DBX and GDB and an encapsulated STABS format for use only with GDB. See the discussion of the `--with-stabs` option of `configure` above for more information on these formats and how to select them.

There is a bug in DEC's assembler that produces incorrect line numbers for ECOFF format when the `.align` directive is used. To work around this problem, GCC will not emit such alignment directives while writing ECOFF format debugging information even if optimization is being performed. Unfortunately, this has the very undesirable side-effect that code addresses when `-O` is specified are different depending on whether or not `-g` is also specified.

To avoid this behavior, specify `-gstabs+` and use GDB instead of DBX. DEC is now aware of this problem with the assembler and hopes to provide a fix shortly.

### alphaev5-cray-unicosmk*

Cray T3E systems running Unicos/Mk.

This port is incomplete and has many known bugs. We hope to improve the support for this target soon. Currently, only the C front end is supported, and it is not possible to build parallel applications. Cray modules are not supported; in particular, Craylibs are assumed to be in `/opt/ctl/craylibs/craylibs`.

You absolutely must use GNU make on this platform. Also, you need to tell GCC where to find the assembler and the linker. The simplest way to do so is by providing `--with-as` and `--with-ld` to `configure`, e.g.

             configure --with-as=/opt/ctl/bin/cam --with-ld=/opt/ctl/bin/cld \
               --enable-languages=c

The comparison test during `make bootstrap` fails on Unicos/Mk because the assembler inserts timestamps into object files. You should be able to work around this by doing `make all` after getting this failure.

### arc-*-elf

Argonaut ARC processor. This configuration is intended for embedded systems.

### arm-*-elf

### xscale-*-*

ARM-family processors. Subtargets that use the ELF object format require GNU binutils 2.13 or newer. Such subtargets include: `arm-*-freebsd`, `arm-*-netbsdelf`, `arm-*-*linux`, `arm-*-rtems` and `arm-*-kaos`.

### arm-*-coff

ARM-family processors. Note that there are two different varieties of PE format subtarget supported: `arm-wince-pe` and `arm-pe` as well as a standard COFF target `arm-*-coff`.

### arm-*-aout

ARM-family processors. These targets support the AOUT file format: `arm-*-aout`, `arm-*-netbsd`.

### avr

ATMEL AVR-family micro controllers. These are used in embedded applications. There are no standard Unix configurations. See "AVR Options" in the main manual for the list of supported MCU types.

Use `configure --target=avr --enable-languages="c"` to configure GCC.

Further installation notes and other useful information about AVR tools can also be obtained from:

- http://www.openavr.org
- http://home.overta.ru/users/denisc/
- http://www.amelek.gda.pl/avr/

We strongly recommend using binutils 2.13 or newer.

The following error:

           Error: register required

indicates that you should upgrade to a newer version of the binutils.

### c4x

Texas Instruments TMS320C3x and TMS320C4x Floating Point Digital Signal Processors. These are used in embedded applications. There are no standard Unix configurations. See "TMS320C3x/C4x Options" in the main manual for the list of supported MCU types.

GCC can be configured as a cross compiler for both the C3x and C4x architectures on the same system. Use `configure --target=c4x --enable-languages="c,c++"` to configure.

Further installation notes and other useful information about C4x tools can also be obtained from:

- http://www.elec.canterbury.ac.nz/c4x/

### CRIS

CRIS is the CPU architecture in Axis Communications ETRAX system-on-a-chip series. These are used in embedded applications.

See "CRIS Options" in the main manual for a list of CRIS-specific options.

There are a few different CRIS targets:

`cris-axis-aout`
  Old target. Includes a multilib for the `elinux` a.out-based target. No multilibs for newer architecture variants.
`cris-axis-elf`
  Mainly for monolithic embedded systems. Includes a multilib for the `v10` core used in `ETRAX 100 LX`.
`cris-axis-linux-gnu`
  A GNU/Linux port for the CRIS architecture, currently targeting `ETRAX 100 LX` by default.

For `cris-axis-aout` and `cris-axis-elf` you need binutils 2.11 or newer. For `cris-axis-linux-gnu` you need binutils 2.12 or newer.

Pre-packaged tools can be obtained from ftp://ftp.axis.com/pub/axis/tools/cris/compiler-kit/. More information about this platform is available at http://developer.axis.com/.

### DOS

Please have a look at our binaries page.

You cannot install GCC by itself on MSDOS; it will not compile under any MSDOS compiler except itself. You need to get the complete compilation package DJGPP, which includes binaries as well as sources, and includes all the necessary compilation tools and libraries.

### dsp16xx

A port to the AT&T DSP1610 family of processors.

### *-*-freebsd*

The version of binutils installed in `/usr/bin` probably works with this release of GCC. However, on FreeBSD 4, bootstrapping against the latest FSF binutils is known to improve overall testsuite results; and, on FreeBSD/alpha, using binutils 2.14 or later is required to build libjava.

Support for FreeBSD 1 was discontinued in GCC 3.2.

Support for FreeBSD 2 will be discontinued after GCC 3.4. The following was true for GCC 3.1 but the current status is unknown. For FreeBSD 2 or any mutant a.out versions of FreeBSD 3: All configuration support and files as shipped with GCC 2.95 are still in place. FreeBSD 2.2.7 has been known to bootstrap completely; however, it is unknown which version of binutils was used (it is assumed that it was the system copy in `/usr/bin`) and C++ EH failures were noted.

For FreeBSD using the ELF file format: DWARF 2 debugging is now the default for all CPU architectures. It had been the default on FreeBSD/alpha since its inception. You may use `-gstabs` instead of `-g`, if you really want the old debugging format. There are no known issues with mixing object files and libraries with different debugging formats. Otherwise, this release of GCC should now match more of the configuration used in the stock FreeBSD configuration of GCC. In particular, `--enable-threads` is now configured by default. However, as a general user, do not attempt to replace the system compiler with this release. Known to bootstrap and check with good results on FreeBSD 4.9-STABLE and 5-CURRENT. In the past, known to bootstrap and check with good results on FreeBSD 3.0, 3.4, 4.0, 4.2, 4.3, 4.4, 4.5, 4.8-STABLE.

In principle, `--enable-threads` is now compatible with `--enable-libgcj` on FreeBSD. However, it has only been built and tested on `i386-*-freebsd[45]` and `alpha-*-freebsd[45]`. The static library may be incorrectly built (symbols are missing at link time). There is a rare timing-based startup hang (probably involves an assumption about the thread library). Multi-threaded boehm-gc (required for libjava) exposes severe threaded signal-handling bugs on FreeBSD before 4.5-RELEASE. Other CPU architectures supported by FreeBSD will require additional configuration tuning in, at the very least, both boehm-gc and libffi.

Shared `libgcc_s.so` is now built and installed by default.

### h8300-hms

Renesas H8/300 series of processors.

Please have a look at our binaries page.

The calling convention and structure layout has changed in release 2.6. All code must be recompiled. The calling convention now passes the first three arguments in function calls in registers. Structures are no longer a multiple of 2 bytes.

### hppa*-hp-hpux*

Support for HP-UX version 9 and older was discontinued in GCC 3.4.

We highly recommend using gas/binutils 2.8 or newer on all hppa platforms; you may encounter a variety of problems when using the HP assembler.

Specifically, `-g` does not work on HP-UX (since that system uses a peculiar debugging format which GCC does not know about), unless you use GAS and GDB and configure GCC with the `--with-gnu-as` and `--with-as=...` options.

If you wish to use the pa-risc 2.0 architecture support with a 32-bit runtime, you must use either the HP assembler, or gas/binutils 2.11 or newer.

There are two default scheduling models for instructions. These are PROCESSOR_7100LC and PROCESSOR_8000. They are selected from the pa-risc architecture specified for the target machine when configuring. PROCESSOR_8000 is the default. PROCESSOR_7100LC is selected when the target is a `hppa1*` machine.

The PROCESSOR_8000 model is not well suited to older processors. Thus, it is important to completely specify the machine architecture when configuring if you want a model other than PROCESSOR_8000. The macro TARGET_SCHED_DEFAULT can be defined in BOOT_CFLAGS if a different default scheduling model is desired.

More specific information to `hppa*-hp-hpux*` targets follows.

### hppa*-hp-hpux10

For hpux10.20, we highly recommend you pick up the latest sed patch `PHCO_19798` from HP. HP has two sites which provide patches free of charge:

- US, Canada, Asia-Pacific, and Latin-America
- http://europe.itrc.hp.com/service/home/home.do Europe.

The HP assembler on these systems has some problems. Most notably the assembler inserts timestamps into each object file it creates, causing the 3-stage comparison test to fail during a `make bootstrap`. You should be able to continue by saying `make all` after getting the failure from `make bootstrap`.

### hppa*-hp-hpux11

GCC 3.0 and up support HP-UX 11. GCC 2.95.x is not supported and cannot be used to compile GCC 3.0 and up.

Refer to binaries for information about obtaining precompiled GCC binaries for HP-UX. Precompiled binaries must be obtained to build the Ada language as it can't be bootstrapped using C. Ada is only available for the 32-bit PA-RISC runtime. The libffi and libjava haven't been ported to HP-UX and don't build.

It is possible to build GCC 3.3 starting with the bundled HP compiler, but the process requires several steps. GCC 3.3 can then be used to build later versions. The fastjar program contains ISO C code and can't be built with the HP bundled compiler. This problem can be avoided by not building the Java language. For example, use the `--enable-languages="c,c++,f77,objc"` option in your configure command.

Starting with GCC 3.4 an ISO C compiler is required to bootstrap. The bundled compiler supports only traditional C; you will need either HP's unbundled compiler, or a binary distribution of GCC.

There are several possible approaches to building the distribution. Binutils can be built first using the HP tools. Then, the GCC distribution can be built. The second approach is to build GCC first using the HP tools, then build binutils, then rebuild GCC. There have been problems with various binary distributions, so it is best not to start from a binary distribution.

On 64-bit capable systems, there are two distinct targets. Different installation prefixes must be used if both are to be installed on the same system. The `hppa[1-2]*-hp-hpux11*` target generates code for the 32-bit PA-RISC runtime architecture and uses the HP linker. The `hppa64-hp-hpux11*` target generates 64-bit code for the PA-RISC 2.0 architecture. The HP and GNU linkers are both supported for this target.

The script config.guess now selects the target type based on the compiler detected during configuration. You must define `PATH` or `CC` so that configure finds an appropriate compiler for the initial bootstrap. When `CC` is used, the definition should contain the options that are needed whenever `CC` is used.

Specifically, options that determine the runtime architecture must be in `CC` to correctly select the target for the build. It is also convenient to place many other compiler options in `CC`. For example, `CC="cc -Ac +DA2.0W -Wp,-H16376 -D_CLASSIC_TYPES -D_HPUX_SOURCE"` can be used to bootstrap the GCC 3.3 branch with the HP compiler in 64-bit K&R/bundled mode. The `+DA2.0W` option will result in the automatic selection of the `hppa64-hp-hpux11*` target. The macro definition table of cpp needs to be increased for a successful build with the HP compiler. _CLASSIC_TYPES and _HPUX_SOURCE need to be defined when building with the bundled compiler, or when using the `-Ac` option. These defines aren't necessary with `-Ae`.

It is best to explicitly configure the `hppa64-hp-hpux11*` target with the `--with-ld=...` option. This overrides the standard search for ld. The two linkers supported on this target require different commands. The default linker is determined during configuration. As a result, it's not possible to switch linkers in the middle of a GCC build. This has been been reported to sometimes occur in unified builds of binutils and GCC.

With GCC 3.0 through 3.2, you must use binutils 2.11 or above. As of GCC 3.3, binutils 2.14 or later is required.

Although the HP assembler can be used for an initial build, it shouldn't be used with any languages other than C and perhaps Fortran due to its many limitations. For example, it does not support weak symbols or alias definitions. As a result, explicit template instantiations are required when using C++. This makes it difficult if not impossible to build many C++ applications. You can't generate debugging information when using the HP assembler. Finally, `make bootstrap` fails in the final comparison of object modules due to the time stamps that it inserts into the modules. The bootstrap can be continued from this point with `make all`.

A recent linker patch must be installed for the correct operation of GCC 3.3 and later. `PHSS_26559` and `PHSS_24304` are the oldest linker patches that are known to work. They are for HP-UX 11.00 and 11.11, respectively. `PHSS_24303`, the companion to `PHSS_24304`, might be usable but it hasn't been tested. These patches have been superseded. Consult the HP patch database to obtain the currently recommended linker patch for your system.

The patches are necessary for the support of weak symbols on the 32-bit port, and for the running of initializers and finalizers. Weak symbols are implemented using SOM secondary definition symbols. Prior to HP-UX 11, there are bugs in the linker support for secondary symbols. The patches correct a problem of linker core dumps creating shared libraries containing secondary symbols, as well as various other linking issues involving secondary symbols.

GCC 3.3 uses the ELF DT_INIT_ARRAY and DT_FINI_ARRAY capabilities to run initializers and finalizers on the 64-bit port. The 32-bit port uses the linker `+init` and `+fini` options for the same purpose. The patches correct various problems with the +init/+fini options, including program core dumps. Binutils 2.14 corrects a problem on the 64-bit port resulting from HP's non-standard use of the .init and .fini sections for array initializers and finalizers.

There are a number of issues to consider in selecting which linker to use with the 64-bit port. The GNU 64-bit linker can only create dynamic binaries. The `-static` option causes linking with archive libraries but doesn't produce a truly static binary. Dynamic binaries still require final binding by the dynamic loader to resolve a set of dynamic-loader-defined symbols. The default behavior of the HP linker is the same as the GNU linker. However, it can generate true 64-bit static binaries using the `+compat` option.

The HP 64-bit linker doesn't support linkonce semantics. As a result, C++ programs have many more sections than they should.

The GNU 64-bit linker has some issues with shared library support and exceptions. As a result, we only support libgcc in archive format. For similar reasons, dwarf2 unwind and exception support are disabled. The GNU linker also has problems creating binaries with `-static`. It doesn't provide stubs for internal calls to global functions in shared libraries, so these calls can't be overloaded.

Thread support is not implemented in GCC 3.0 through 3.2, so the `--enable-threads` configure option does not work. In 3.3 and later, POSIX threads are supported. The optional DCE thread library is not supported.

This port still is undergoing significant development.

### i370-*-*

This port is very preliminary and has many known bugs. We hope to have a higher-quality port for this machine soon.

### *-*-linux-gnu

Versions of libstdc++-v3 starting with 3.2.1 require bugfixes present in glibc 2.2.5 and later. More information is available in the libstdc++-v3 documentation.

### i?86-*-linux*aout

Use this configuration to generate `a.out` binaries on Linux-based GNU systems. This configuration is being superseded.

### i?86-*-linux*

As of GCC 3.3, binutils 2.13.1 or later is required for this platform. See bug 10877 for more information.

If you receive Signal 11 errors when building on GNU/Linux, then it is possible you have a hardware problem. Further information on this can be found on www.bitwizard.nl.

Some recent versions of GNU/Linux, such as Fedora Core 1, support exec-shield-randomize. Turning this on interferes with precompiled headers. If you need to use precompiled headers, exec-shield-randomize can be turned off for the entire system by editing `/etc/sysctl.conf` and adding a line:

         kernel.exec-shield-randomize = 0

You may then need to run `sysctl -p`.

This will be fixed in future releases of GCC.

### i?86-*-sco3.2v5*

Use this for the SCO OpenServer Release 5 family of operating systems.

Unlike earlier versions of GCC, the ability to generate COFF with this target is no longer provided.

Earlier versions of GCC emitted DWARF 1 when generating ELF to allow the system debugger to be used. That support was too burdensome to maintain. GCC now emits only DWARF 2 for this target. This means you may use either the UDK debugger or GDB to debug programs built by this version of GCC.

GCC is now only supported on releases 5.0.4 and later, and requires that you install Support Level Supplement OSS646B or later, and Support Level Supplement OSS631C or later. If you are using release 5.0.7 of OpenServer, you must have at least the first maintenance pack installed (this includes the relevant portions of OSS646). OSS646, also known as the "Execution Environment Update", provides updated link editors and assemblers, as well as updated standard C and math libraries. The C startup modules are also updated to support the System V gABI draft, and GCC relies on that behavior. OSS631 provides a collection of commonly used open source libraries, some of which GCC depends on (such as GNU gettext and zlib). SCO OpenServer Release 5.0.7 has all of this built in by default, but OSS631C and later also apply to that release. Please visit ftp://ftp.sco.com/pub/openserver5 for the latest versions of these (and other potentially useful) supplements.

Although there is support for using the native assembler, it is recommended that you configure GCC to use the GNU assembler. You do this by using the flags `--with-gnu-as`. You should use a modern version of GNU binutils. Version 2.13.2.1 was used for all testing. In general, only the `--with-gnu-as` option is tested. A modern bintuils (as well as a plethora of other development related GNU utilities) can be found in Support Level Supplement OSS658A, the "GNU Development Tools" package. See the SCO web and ftp sites for details. That package also contains the currently "officially supported" version of GCC, version 2.95.3. It is useful for bootstrapping this version.

### i?86-*-udk

This target emulates the SCO Universal Development Kit and requires that package be installed. (If it is installed, you will have a `/udk/usr/ccs/bin/cc` file present.) It's very much like the `i?86-*-unixware7*` target but is meant to be used when hosting on a system where UDK isn't the default compiler such as OpenServer 5 or Unixware 2. This target will generate binaries that will run on OpenServer, Unixware 2, or Unixware 7, with the same warnings and caveats as the SCO UDK.

This target is a little tricky to build because we have to distinguish it from the native tools (so it gets headers, startups, and libraries from the right place) while making the tools not think we're actually building a cross compiler. The easiest way to do this is with a configure command like this:

             CC=/udk/usr/ccs/bin/cc /your/path/to/gcc/configure \
               --host=i686-pc-udk --target=i686-pc-udk --program-prefix=udk-

You should substitute `i686` in the above command with the appropriate processor for your host.

After the usual `make bootstrap` and `make install`, you can then access the UDK-targeted GCC tools by adding `udk-` before the commonly known name. For example, to invoke the C compiler, you would use `udk-gcc`. They will coexist peacefully with any native-target GCC tools you may have installed.

### ia64-*-linux

IA-64 processor (also known as IPF, or Itanium Processor Family) running GNU/Linux.

If you are using the optional libunwind library, then you must use libunwind 0.96 or later.

None of the following versions of GCC has an ABI that is compatible with any of the other versions in this list, with the exception that Red Hat 2.96 and Trillian 000171 are compatible with each other: 3.1, 3.0.2, 3.0.1, 3.0, Red Hat 2.96, and Trillian 000717. This primarily affects C++ programs and programs that create shared libraries. GCC 3.1 or later is recommended for compiling linux, the kernel. As of version 3.1 GCC is believed to be fully ABI compliant, and hence no more major ABI changes are expected.

### ia64-*-hpux*

Building GCC on this target requires the GNU Assembler. The bundled HP assembler will not work. To prevent GCC from using the wrong assembler, the option `--with-gnu-as` may be necessary.

The GCC libunwind library has not been ported to HPUX. This means that for GCC versions 3.2.3 and earlier, `--enable-libunwind-exceptions` is required to build GCC. For GCC 3.3 and later, this is the default.

### *-ibm-aix*

Support for AIX version 3 and older was discontinued in GCC 3.4.

AIX Make frequently has problems with GCC makefiles. GNU Make 3.79.1 or newer is recommended to build on this platform.

To speed up the configuration phases of bootstrapping and installing GCC, one may use GNU Bash instead of AIX `/bin/sh`, e.g.,

            % CONFIG_SHELL=/opt/freeware/bin/bash
            % export CONFIG_SHELL

and then proceed as described in the build instructions, where we strongly recommend using GNU make and specifying an absolute path to invoke srcdir/configure.

Errors involving `alloca` when building GCC generally are due to an incorrect definition of `CC` in the Makefile or mixing files compiled with the native C compiler and GCC. During the stage1 phase of the build, the native AIX compiler must be invoked as `cc` (not `xlc`). Once `configure` has been informed of `xlc`, one needs to use `make distclean` to remove the configure cache files and ensure that `CC` environment variable does not provide a definition that will confuse `configure`. If this error occurs during stage2 or later, then the problem most likely is the version of Make (see above).

The native `as` and `ld` are recommended for bootstrapping on AIX 4 and required for bootstrapping on AIX 5L. The GNU Assembler reports that it supports WEAK symbols on AIX 4, which causes GCC to try to utilize weak symbol functionality although it is not supported. The GNU Assembler and Linker do not support AIX 5L sufficiently to bootstrap GCC. The native AIX tools do interoperate with GCC.

Building `libstdc++.a` requires a fix for an AIX Assembler bug APAR IY26685 (AIX 4.3) or APAR IY25528 (AIX 5.1). It also requires a fix for another AIX Assembler bug and a co-dependent AIX Archiver fix referenced as APAR IY53606 (AIX 5.2) or a APAR IY54774 (AIX 5.1)

`libstdc++` in GCC 3.4 increments the major version number of the shared object and GCC installation places the `libstdc++.a` shared library in a common location which will overwrite the and GCC 3.3 version of the shared library. Applications either need to be re-linked against the new shared library or the GCC 3.1 and GCC 3.3 versions of the `libstdc++` shared object needs to be available to the AIX runtime loader. The GCC 3.1 `libstdc++.so.4`, if present, and GCC 3.3 `libstdc++.so.5` shared objects can be installed for runtime dynamic loading using the following steps to set the `F_LOADONLY` flag in the shared object for each multilib `libstdc++.a` installed:

Extract the shared objects from the currently installed `libstdc++.a` archive:

            % ar -x libstdc++.a libstdc++.so.4 libstdc++.so.5

Enable the `F_LOADONLY` flag so that the shared object will be available for runtime dynamic loading, but not linking:

            % strip -e libstdc++.so.4 libstdc++.so.5

Archive the runtime-only shared object in the GCC 3.4 `libstdc++.a` archive:

            % ar -q libstdc++.a libstdc++.so.4 libstdc++.so.5

Linking executables and shared libraries may produce warnings of duplicate symbols. The assembly files generated by GCC for AIX always have included multiple symbol definitions for certain global variable and function declarations in the original program. The warnings should not prevent the linker from producing a correct library or runnable executable.

AIX 4.3 utilizes a "large format" archive to support both 32-bit and 64-bit object modules. The routines provided in AIX 4.3.0 and AIX 4.3.1 to parse archive libraries did not handle the new format correctly. These routines are used by GCC and result in error messages during linking such as "not a COFF file". The version of the routines shipped with AIX 4.3.1 should work for a 32-bit environment. The `-g` option of the archive command may be used to create archives of 32-bit objects using the original "small format". A correct version of the routines is shipped with AIX 4.3.2 and above.

Some versions of the AIX binder (linker) can fail with a relocation overflow severe error when the `-bbigtoc` option is used to link GCC-produced object files into an executable that overflows the TOC. A fix for APAR IX75823 (OVERFLOW DURING LINK WHEN USING GCC AND -BBIGTOC) is available from IBM Customer Support and from its techsupport.services.ibm.com website as PTF U455193.

The AIX 4.3.2.1 linker (bos.rte.bind_cmds Level 4.3.2.1) will dump core with a segmentation fault when invoked by any version of GCC. A fix for APAR IX87327 is available from IBM Customer Support and from its techsupport.services.ibm.com website as PTF U461879. This fix is incorporated in AIX 4.3.3 and above.

The initial assembler shipped with AIX 4.3.0 generates incorrect object files. A fix for APAR IX74254 (64BIT DISASSEMBLED OUTPUT FROM COMPILER FAILS TO ASSEMBLE/BIND) is available from IBM Customer Support and from its techsupport.services.ibm.com website as PTF U453956. This fix is incorporated in AIX 4.3.1 and above.

AIX provides National Language Support (NLS). Compilers and assemblers use NLS to support locale-specific representations of various data formats including floating-point numbers (e.g., `.` vs `,` for separating decimal fractions). There have been problems reported where GCC does not produce the same floating-point formats that the assembler expects. If one encounters this problem, set the `LANG` environment variable to `C` or `En_US`.

By default, GCC for AIX 4.1 and above produces code that can be used on both Power or PowerPC processors.

A default can be specified with the `-mcpu=`cpu_type`` switch and using the configure option `--with-cpu-`cpu_type``.

### ip2k-*-elf

Ubicom IP2022 micro controller. This configuration is intended for embedded systems. There are no standard Unix configurations.

Use `configure --target=ip2k-elf --enable-languages=c` to configure GCC.

### iq2000-*-elf

Vitesse IQ2000 processors. These are used in embedded applications. There are no standard Unix configurations.

### m32r-*-elf

Renesas M32R processor. This configuration is intended for embedded systems.

### m6811-elf

Motorola 68HC11 family micro controllers. These are used in embedded applications. There are no standard Unix configurations.

### m6812-elf

Motorola 68HC12 family micro controllers. These are used in embedded applications. There are no standard Unix configurations.

### m68k-hp-hpux

HP 9000 series 300 or 400 running HP-UX. HP-UX version 8.0 has a bug in the assembler that prevents compilation of GCC. This bug manifests itself during the first stage of compilation, while building `libgcc2.a`:

         _floatdisf
         cc1: warning: `-g' option not supported on this version of GCC
         cc1: warning: `-g1' option not supported on this version of GCC
         ./xgcc: Internal compiler error: program as got fatal signal 11

A patched version of the assembler is available as the file ftp://altdorf.ai.mit.edu/archive/cph/hpux-8.0-assembler. If you have HP software support, the patch can also be obtained directly from HP, as described in the following note:

> This is the patched assembler, to patch SR#1653-010439, where the assembler aborts on floating point constants.

> The bug is not really in the assembler, but in the shared library version of the function "cvtnum(3c)". The bug on "cvtnum(3c)" is SR#4701-078451. Anyway, the attached assembler uses the archive library version of "cvtnum(3c)" and thus does not exhibit the bug.

This patch is also known as PHCO_4484.

In addition gdb does not understand that native HP-UX format, so you must use gas if you wish to use gdb.

On HP-UX version 8.05, but not on 8.07 or more recent versions, the `fixproto` shell script triggers a bug in the system shell. If you encounter this problem, upgrade your operating system or use BASH (the GNU shell) to run `fixproto`. This bug will cause the fixproto program to report an error of the form:

         ./fixproto: sh internal 1K buffer overflow

To fix this, you can also change the first line of the fixproto script to look like:

         #!/bin/ksh

### mips-*-*

If on a MIPS system you get an error message saying "does not have gp sections for all it's [sic] sectons [sic]", don't worry about it. This happens whenever you use GAS with the MIPS linker, but there is not really anything wrong, and it is okay to use the output file. You can stop such warnings by installing the GNU linker.

It would be nice to extend GAS to produce the gp tables, but they are optional, and there should not be a warning about their absence.

The libstdc++ atomic locking routines for MIPS targets requires MIPS II and later. A patch went in just after the GCC 3.3 release to make `mips*-*-*` use the generic implementation instead. You can also configure for `mipsel-elf` as a workaround. The `mips*-*-linux*` target continues to use the MIPS II routines. More work on this is expected in future releases.

Cross-compilers for the Mips as target using the Mips assembler currently do not work, because the auxiliary programs `mips-tdump.c` and `mips-tfile.c` can't be compiled on anything but a Mips. It does work to cross compile for a Mips if you use the GNU assembler and linker.

### mips-sgi-irix5

In order to compile GCC on an SGI running IRIX 5, the `compiler_dev.hdr` subsystem must be installed from the IDO CD-ROM supplied by SGI. It is also available for download from ftp://ftp.sgi.com/sgi/IRIX5.3/iris-development-option-5.3.tardist.

If you use the MIPS C compiler to bootstrap, it may be necessary to increase its table size for switch statements with the `-Wf,-XNg1500` option. If you use the `-O2` optimization option, you also need to use `-Olimit 3000`.

To enable debugging under IRIX 5, you must use GNU binutils 2.15 or later, and use the `--with-gnu-as` and `--with-gnu-ld` `configure` options when configuring GCC. You need to use GNU `ar` and `nm`, also distributed with GNU binutils.

### mips-sgi-irix6

If you are using SGI's MIPSpro `cc` as your bootstrap compiler, you must ensure that the N32 ABI is in use. To test this, compile a simple C file with `cc` and then run `file` on the resulting object file. The output should look like:

         test.o: ELF N32 MSB ...

If you see:

         test.o: ELF 32-bit MSB ...

or

         test.o: ELF 64-bit MSB ...

then your version of `cc` uses the O32 or N64 ABI by default. You should set the environment variable `CC` to `cc -n32` before configuring GCC. SGI's MIPSpro 7.2 assembler may misassemble parts of the compiler, causing bootstrap failures. MIPSpro 7.3 is known to work. MIPSpro C 7.4 may cause bootstrap failures, too, due to a bug when inlining `memcmp`. Either add `-U__INLINE_INTRINSICS` to the `CC` environment variable as a workaround or upgrade to MIPSpro C 7.4.1m.

If you want the resulting `gcc` to run on old 32-bit systems with the MIPS R4400 CPU, you need to ensure that only code for the `mips3` instruction set architecture (ISA) is generated. While GCC 3.x does this correctly, both GCC 2.95 and SGI's MIPSpro `cc` may change the ISA depending on the machine where GCC is built. Using one of them as the bootstrap compiler may result in `mips4` code, which won't run at all on `mips3`-only systems. For the test program above, you should see:

         test.o: ELF N32 MSB mips-3 ...

If you get:

         test.o: ELF N32 MSB mips-4 ...

instead, you should set the environment variable `CC` to `cc -n32 -mips3` or `gcc -mips3` respectively before configuring GCC.

GCC on IRIX 6 is usually built to support the N32, O32 and N64 ABIs. If you build GCC on a system that doesn't have the N64 libraries installed or cannot run 64-bit binaries, you need to configure with `--disable-multilib` so GCC doesn't try to use them. This will disable building the O32 libraries, too. Look for `/usr/lib64/libc.so.1` to see if you have the 64-bit libraries installed.

To enable debugging for the O32 ABI, you must use GNU `as` from GNU binutils 2.15 or later. You may also use GNU `ld`, but this is not required and currently causes some problems with Ada.

The `--enable-threads` option doesn't currently work, a patch is in preparation for a future release. The `--enable-libgcj` option is disabled by default: IRIX 6 uses a very low default limit (20480) for the command line length. Although `libtool` contains a workaround for this problem, at least the N64 `libgcj` is known not to build despite this, running into an internal error of the native `ld`. A sure fix is to increase this limit (`ncargs`) to its maximum of 262144 bytes. If you have root access, you can use the `systune` command to do this.

See http://freeware.sgi.com/ for more information about using GCC on IRIX platforms.

### powerpc-*-*

You can specify a default version for the `-mcpu=`cpu_type`` switch by using the configure option `--with-cpu-`cpu_type``.

### powerpc-*-darwin*

PowerPC running Darwin (Mac OS X kernel).

Pre-installed versions of Mac OS X may not include any developer tools, meaning that you will not be able to build GCC from source. Tool binaries are available at http://developer.apple.com/tools/compilers.html (free registration required).

The default stack limit of 512K is too small, which may cause compiles to fail with 'Bus error'. Set the stack larger, for instance by doing `limit stack 800`. It's a good idea to use the GNU preprocessor instead of Apple's `cpp-precomp` during the first stage of bootstrapping; this is automatic when doing `make bootstrap`, but to do it from the toplevel objdir you will need to say `make CC='cc -no-cpp-precomp' bootstrap`.

The version of GCC shipped by Apple typically includes a number of extensions not available in a standard GCC release. These extensions are generally specific to Mac programming.

### powerpc-*-elf, powerpc-*-sysv4

PowerPC system in big endian mode, running System V.4.

### powerpc-*-linux-gnu*

You will need binutils 2.13.90.0.10 or newer for a working GCC.

### powerpc-*-netbsd*

PowerPC system in big endian mode running NetBSD. To build the documentation you will need Texinfo version 4.2 (NetBSD 1.5.1 included Texinfo version 3.12).

### powerpc-*-eabisim

Embedded PowerPC system in big endian mode for use in running under the PSIM simulator.

### powerpc-*-eabi

Embedded PowerPC system in big endian mode.

### powerpcle-*-elf, powerpcle-*-sysv4

PowerPC system in little endian mode, running System V.4.

### powerpcle-*-eabisim

Embedded PowerPC system in little endian mode for use in running under the PSIM simulator.

### powerpcle-*-eabi

Embedded PowerPC system in little endian mode.

### s390-*-linux*

S/390 system running GNU/Linux for S/390.

### s390x-*-linux*

zSeries system (64-bit) running GNU/Linux for zSeries.

### s390x-ibm-tpf*

zSeries system (64-bit) running TPF. This platform is supported as cross-compilation target only.

### *-*-solaris2*

Sun does not ship a C compiler with Solaris 2. To bootstrap and install GCC you first have to install a pre-built compiler, see our binaries page for details.

The Solaris 2 `/bin/sh` will often fail to configure `libstdc++-v3`, `boehm-gc` or `libjava`. We therefore recommend to use the following sequence of commands to bootstrap and install GCC:

            % CONFIG_SHELL=/bin/ksh
            % export CONFIG_SHELL

and then proceed as described in the build instructions, where we strongly recommend using GNU make and specifying an absolute path to invoke srcdir/configure.

Solaris 2 comes with a number of optional OS packages. Some of these are needed to use GCC fully, namely `SUNWarc`, `SUNWbtool`, `SUNWesu`, `SUNWhea`, `SUNWlibm`, `SUNWsprot`, and `SUNWtoo`. If you did not install all optional packages when installing Solaris 2, you will need to verify that the packages that GCC needs are installed.

To check whether an optional package is installed, use the `pkginfo` command. To add an optional package, use the `pkgadd` command. For further details, see the Solaris 2 documentation.

Trying to use the linker and other tools in `/usr/ucb` to install GCC has been observed to cause trouble. For example, the linker may hang indefinitely. The fix is to remove `/usr/ucb` from your `PATH`.

The build process works more smoothly with the legacy Sun tools so, if you have `/usr/xpg4/bin` in your `PATH`, we recommend that you place `/usr/bin` before `/usr/xpg4/bin` for the duration of the build.

All releases of GNU binutils prior to 2.11.2 have known bugs on this platform. We recommend the use of GNU binutils 2.11.2 or the vendor tools (Sun `as`, Sun `ld`).

Sun bug 4296832 turns up when compiling X11 headers with GCC 2.95 or newer: `g++` will complain that types are missing. These headers assume that omitting the type means `int`; this assumption worked for C89 but is wrong for C++, and is now wrong for C99 also.

`g++` accepts such (invalid) constructs with the option `-fpermissive`; it will assume that any missing type is `int` (as defined by C89).

There are patches for Solaris 2.6 (105633-56 or newer for SPARC, 106248-42 or newer for Intel), Solaris 7 (108376-21 or newer for SPARC, 108377-20 for Intel), and Solaris 8 (108652-24 or newer for SPARC, 108653-22 for Intel) that fix this bug.

### sparc-sun-solaris2*

When GCC is configured to use binutils 2.11.2 or later the binaries produced are smaller than the ones produced using Sun's native tools; this difference is quite significant for binaries containing debugging information.

Sun `as` 4.x is broken in that it cannot cope with long symbol names. A typical error message might look similar to the following:

         /usr/ccs/bin/as: "/var/tmp/ccMsw135.s", line 11041: error:
           can't compute value of an expression involving an external symbol.

This is Sun bug 4237974. This is fixed with patch 108908-02 for Solaris 2.6 and has been fixed in later (5.x) versions of the assembler, starting with Solaris 7.

Starting with Solaris 7, the operating system is capable of executing 64-bit SPARC V9 binaries. GCC 3.1 and later properly supports this; the `-m64` option enables 64-bit code generation. However, if all you want is code tuned for the UltraSPARC CPU, you should try the `-mtune=ultrasparc` option instead, which produces code that, unlike full 64-bit code, can still run on non-UltraSPARC machines.

When configuring on a Solaris 7 or later system that is running a kernel that supports only 32-bit binaries, one must configure with `--disable-multilib`, since we will not be able to build the 64-bit target libraries.

GCC 3.3 and GCC 3.4 trigger code generation bugs in earlier versions of the GNU compiler (especially GCC 3.0.x versions), which lead to the miscompilation of the stage1 compiler and the subsequent failure of the bootstrap process. A workaround is to use GCC 3.2.3 as an intermediary stage, i.e. to bootstrap that compiler with the base compiler and then use it to bootstrap the final compiler.

GCC 3.4 triggers a code generation bug in versions 5.4 (Sun ONE Studio 7) and 5.5 (Sun ONE Studio 8) of the Sun compiler, which causes a bootstrap failure in form of a miscompilation of the stage1 compiler by the Sun compiler. This is Sun bug 4974440. This is fixed with patch 112760-07.

GCC 3.4 changed the default debugging format from STABS to DWARF-2 for 32-bit code on Solaris 7 and later. If you are using the Sun assembler, this change apparently runs afoul of Sun bug 4910101, for which (as of 2004-05-23) there is no fix. A symptom of the problem is that you cannot compile C++ programs like `groff` 1.19.1 without getting messages like `ld: warning: relocation error: R_SPARC_UA32 ... external symbolic relocation against non-allocatable section .debug_info; cannot be processed at runtime: relocation ignored`. To work around this problem, compile with `-gstabs+` instead of plain `-g`.

### sparc-sun-solaris2.7

Sun patch 107058-01 (1999-01-13) for Solaris 7/SPARC triggers a bug in the dynamic linker. This problem (Sun bug 4210064) affects GCC 2.8 and later, including all EGCS releases. Sun formerly recommended 107058-01 for all Solaris 7 users, but around 1999-09-01 it started to recommend it only for people who use Sun's compilers.

Here are some workarounds to this problem:

- Do not install Sun patch 107058-01 until after Sun releases a complete patch for bug 4210064. This is the simplest course to take, unless you must also use Sun's C compiler. Unfortunately 107058-01 is preinstalled on some new Solaris 7-based hosts, so you may have to back it out.
- Copy the original, unpatched Solaris 7 `/usr/ccs/bin/as` into `/usr/local/libexec/gcc/sparc-sun-solaris2.7/3.4/as`, adjusting the latter name to fit your local conventions and software version numbers.
- Install Sun patch 106950-03 (1999-05-25) or later. Nobody with both 107058-01 and 106950-03 installed has reported the bug with GCC and Sun's dynamic linker. This last course of action is riskiest, for two reasons. First, you must install 106950 on all hosts that run code generated by GCC; it doesn't suffice to install it only on the hosts that run GCC itself. Second, Sun says that 106950-03 is only a partial fix for bug 4210064, but Sun doesn't know whether the partial fix is adequate for GCC. Revision -08 or later should fix the bug. The current (as of 2004-05-23) revision is -24, and is included in the Solaris 7 Recommended Patch Cluster.

GCC 3.3 triggers a bug in version 5.0 Alpha 03/27/98 of the Sun assembler, which causes a bootstrap failure when linking the 64-bit shared version of libgcc. A typical error message is:

         ld: fatal: relocation error: R_SPARC_32: file libgcc/sparcv9/_muldi3.o:
           symbol <unknown>:  offset 0xffffffff7ec133e7 is non-aligned.

This bug has been fixed in the final 5.0 version of the assembler.

### sparc-*-linux*

GCC versions 3.0 and higher require binutils 2.11.2 and glibc 2.2.4 or newer on this platform. All earlier binutils and glibc releases mishandled unaligned relocations on `sparc-*-*` targets.

### sparc64-*-solaris2*

The following compiler flags must be specified in the configure step in order to bootstrap this target with the Sun compiler:

            % CC="cc -xildoff -xarch=v9" srcdir/configure [options] [target]

`-xildoff` turns off the incremental linker, and `-xarch=v9` specifies the SPARC-V9 architecture to the Sun linker and assembler.

### sparcv9-*-solaris2*

This is a synonym for sparc64-*-solaris2*.

### *-*-sysv*

On System V release 3, you may get this error message while linking:

         ld fatal: failed to write symbol name something
          in strings table for file whatever

This probably indicates that the disk is full or your ulimit won't allow the file to be as large as it needs to be.

This problem can also result because the kernel parameter `MAXUMEM` is too small. If so, you must regenerate the kernel and make the value much larger. The default value is reported to be 1024; a value of 32768 is said to work. Smaller values may also work.

On System V, if you get an error like this,

         /usr/local/lib/bison.simple: In function `yyparse':
         /usr/local/lib/bison.simple:625: virtual memory exhausted

that too indicates a problem with disk space, ulimit, or `MAXUMEM`.

On a System V release 4 system, make sure `/usr/bin` precedes `/usr/ucb` in `PATH`. The `cc` command in `/usr/ucb` uses libraries which have bugs.

### vax-dec-ultrix

Don't try compiling with VAX C (`vcc`). It produces incorrect code in some cases (for example, when `alloca` is used).

### *-*-vxworks*

Support for VxWorks is in flux. At present GCC supports only the very recent VxWorks 5.5 (aka Tornado 2.2) release, and only on PowerPC. We welcome patches for other architectures supported by VxWorks 5.5. Support for VxWorks AE would also be welcome; we believe this is merely a matter of writing an appropriate "configlette" (see below). We are not interested in supporting older, a.out or COFF-based, versions of VxWorks in GCC 3.

VxWorks comes with an older version of GCC installed in ``$WIND_BASE`/host`; we recommend you do not overwrite it. Choose an installation prefix entirely outside $WIND_BASE. Before running `configure`, create the directories ``prefix`` and ``prefix`/bin`. Link or copy the appropriate assembler, linker, etc. into ``prefix`/bin`, and set your PATH to include that directory while running both `configure` and `make`.

You must give `configure` the `--with-headers=`$WIND_BASE`/target/h` switch so that it can find the VxWorks system headers. Since VxWorks is a cross compilation target only, you must also specify `--target=`target``. `configure` will attempt to create the directory ``prefix`/`target`/sys-include` and copy files into it; make sure the user running `configure` has sufficient privilege to do so.

GCC's exception handling runtime requires a special "configlette" module, `contrib/gthr_supp_vxw_5x.c`. Follow the instructions in that file to add the module to your kernel build. (Future versions of VxWorks will incorporate this module.)

### x86_64-*-*, amd64-*-*

GCC supports the x86-64 architecture implemented by the AMD64 processor (amd64-*-* is an alias for x86_64-*-*) on GNU/Linux, FreeBSD and NetBSD. On GNU/Linux the default is a bi-arch compiler which is able to generate both 64-bit x86-64 and 32-bit x86 code (via the `-m32` switch).

### xtensa-*-elf

This target is intended for embedded Xtensa systems using the `newlib` C library. It uses ELF but does not support shared objects. Designed-defined instructions specified via the Tensilica Instruction Extension (TIE) language are only supported through inline assembly.

The Xtensa configuration information must be specified prior to building GCC. The `include/xtensa-config.h` header file contains the configuration information. If you created your own Xtensa configuration with the Xtensa Processor Generator, the downloaded files include a customized copy of this header file, which you can use to replace the default header file.

### xtensa-*-linux*

This target is for Xtensa systems running GNU/Linux. It supports ELF shared objects and the GNU C library (glibc). It also generates position-independent code (PIC) regardless of whether the `-fpic` or `-fPIC` options are used. In other respects, this target is the same as the `xtensa-*-elf` target.

### Microsoft Windows (32-bit)

A port of GCC 2.95.2 and 3.x is included with the Cygwin environment.

Current (as of early 2001) snapshots of GCC will build under Cygwin without modification.

GCC does not currently build with Microsoft's C++ compiler and there are no plans to make it do so.

### OS/2

GCC does not currently support OS/2. However, Andrew Zabolotny has been working on a generic OS/2 port with pgcc. The current code can be found at http://www.goof.com/pcg/os2/.

An older copy of GCC 2.8.1 is included with the EMX tools available at ftp://ftp.leo.org/pub/comp/os/os2/leo/devtools/emx+gcc/.

### Older systems

GCC contains support files for many older (1980s and early 1990s) Unix variants. For the most part, support for these systems has not been deliberately removed, but it has not been maintained for several years and may suffer from bitrot.

Starting with GCC 3.1, each release has a list of "obsoleted" systems. Support for these systems is still present in that release, but `configure` will fail unless the `--enable-obsolete` option is given. Unless a maintainer steps forward, support for these systems will be removed from the next release of GCC.

Support for old systems as hosts for GCC can cause problems if the workarounds for compiler, library and operating system bugs affect the cleanliness or maintainability of the rest of GCC. In some cases, to bring GCC up on such a system, if still possible with current GCC, may require first installing an old version of GCC which did work on that system, and using it to compile a more recent GCC, to avoid bugs in the vendor compiler. Old releases of GCC 1 and GCC 2 are available in the `old-releases` directory on the GCC mirror sites. Header bugs may generally be avoided using `fixincludes`, but bugs or deficiencies in libraries and the operating system may still cause problems.

Support for older systems as targets for cross-compilation is less problematic than support for them as hosts for GCC; if an enthusiast wishes to make such a target work again (including resurrecting any of the targets that never worked with GCC 2, starting from the last CVS version before they were removed), patches following the usual requirements would be likely to be accepted, since they should not affect the support for more modern targets.

For some systems, old versions of GNU binutils may also be useful, and are available from `pub/binutils/old-releases` on sources.redhat.com mirror sites.

Some of the information on specific systems above relates to such older systems, but much of the information about GCC on such systems (which may no longer be applicable to current GCC) is to be found in the GCC texinfo manual.

### all ELF targets (SVR4, Solaris 2, etc.)

C++ support is significantly better on ELF targets if you use the GNU linker; duplicate copies of inlines, vtables and template instantiations will be discarded automatically.

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