   Copyright (C) 2010, 2011, 2012, 2013 Free Software Foundation, Inc.
   
   Copying and distribution of this file, with or without modification,
   are permitted in any medium without royalty provided the copyright
   notice and this notice are preserved.

Changes from 4.0.2 to 4.1.0
---------------------------

1. The three executables gawk, pgawk, and dgawk, have been merged into
   one, named just gawk.  As a result:
   	* The -R option is gone
	* Use -D to run the debugger. An optional file argument is a
	  list of commands to run first.
	* Use -o to do pretty-printing only.
	* Use -p to do profiling.
   This considerably reduces gawk's "footprint" and eases the documentation
   burden as well.

2. Gawk now supports high precision arithmetic with MPFR.  The default is
   still double precision, but setting PREC changes things, or using
   the -M / --bignum options.  This support is not compiled in if the MPFR
   library is not available.

3. The new -i option (from xgawk) is used for loading awk library files.
   This differs from -f in that the first non-option argument is treated
   as a script.

4. The new -l option (from xgawk) is used for loading dynamic extensions.

5. The dynamic extension interface has been completely redone!  There is
   now a defined API for C extensions to use.  A C extension acts like
   a function written in awk, except that it cannot do everything that awk
   code can. However, this allows interfacing to any facility that is
   available from C.  This is a major development, see the doc, which has
   a nice shiny new chapter describing everything.

   This support is not compiled in if dynamic loading of shared libraries
   is not supported.

   The old extension mechanism is still supported for compatiblity, but
   it will most definitely be removed at the next major release.

6. The "inplace" extension, built using the new facility, can be used to
   simulate the GNU "sed -i" feature.

7. The and(), or() and xor() functions now take any number of arguments,
   with a minimum of two.

8. New arrays: SYMTAB, FUNCTAB, and PROCINFO["identifiers"]. SYMTAB allows
   indirect access to any defined variable or array; it is possible to
   "walk" the symbol table, if that should be necessary.

9. Support for building gawk with a cross compiler has been improved.

10. Infrastructure upgrades: bison 2.7.1, gettext 0.18.2.1, automake 1.13.1,
    libtool 2.4.2 for the extensions.

Changes from 4.0.1 to 4.0.2
---------------------------

1. Infrastructure upgrades: Autoconf 2.69, Automake 1.12.6, bison 2.7.

2. `fflush()', `nextfile', and `delete array' are all now part of POSIX.

3. fflush() behavior changed to match BWK awk and for POSIX - now both
   fflush() and fflush("") flush all open output redirections.

4. Various minor bug fixes and documentation updates.
 
Changes from 4.0.0 to 4.0.1
---------------------------

1. The default handling of backslash in sub() and gsub() has been reverted to
   the behavior of 3.1. It was silly to think I could break compatibility that
   way, even for standards compliance.

2. Completed the implementation of Rational Range Interpretation.

3. Failure to get the group set is no longer a fatal error.

4. Lots of minor bugs fixed and portability clean-ups along the way. See
   the ChangeLog for details.

Changes from 3.1.8 to 4.0.0
---------------------------

1. The special files /dev/pid, /dev/ppid, /dev/pgrpid and /dev/user are
   now completely gone. Use PROCINFO instead.

2. The POSIX 2008 behavior for `sub' and `gsub' are now the default.
   THIS CHANGES BEHAVIOR!!!!

3. The \s and \S escape sequences are now recognized in regular expressions.

4. The split() function accepts an optional fourth argument which is an array
   to hold the values of the separators.

5. The new -b / --characters-as-bytes option means "hands off my data"; gawk
   won't try to treat input as a multibyte string.

6. There is a new --sandbox option; see the doc.

7. Indirect function calls are now available.

8. Interval expressions are now part of default regular expressions for
   GNU Awk syntax.

9. --gen-po is now correctly named --gen-pot.

10. switch / case is now enabled by default. There's no longer a need
    for a configure-time option.

11. Gawk now supports BEGINFILE and ENDFILE. See the doc for details.

12. Directories named on the command line now produce a warning, not
    a fatal error, unless --posix or --traditional.

13. The new FPAT variable allows you to specify a regexp that matches
    the fields, instead of matching the field separator. The new patsplit()
    function gives the same capability for splitting.

14. All long options now have short options, for use in `#!' scripts.

15. Support for IPv6 is added via the /inet6/... special file. /inet4/...
    forces IPv4 and /inet chooses the system default (probably IPv4).

16. Added a warning for /[:space:]/ that should be /[[:space:]]/.

17. Merged with John Haque's byte code internals. Adds dgawk debugger and
    possibly improved performance.

18. `break' and `continue' are no longer valid outside a loop, even with
    --traditional.

19. POSIX character classes work with --traditional (BWK awk supports them).

20. Nuked redundant --compat, --copyleft, and --usage long options.

21. Arrays of arrays added. See the doc.

22. Per the GNU Coding Standards, dynamic extensions must now define
    a global symbol indicating that they are GPL-compatible. See
    the documentation and example extensions.
    THIS CHANGES BEHAVIOR!!!!

23. In POSIX mode, string comparisons use strcoll/wcscoll.
    THIS CHANGES BEHAVIOR!!!!

24. The option for raw sockets was removed, since it was never implemented.

25. Gawk now treats ranges of the form [d-h] as if they were in the C
    locale, no matter what kind of regexp is being used, and even if
    --posix.  The latest POSIX standard allows this, and the documentation
    has been updated.  Maybe this will stop all the questions about
    [a-z] matching uppercase letters.
    THIS CHANGES BEHAVIOR!!!!

26. PROCINFO["strftime"] now holds the default format for strftime().

27. Updated to latest infrastructure: Autoconf 2.68, Automake 1.11.1,
    Gettext 0.18.1, Bison 2.5.

28. Many code cleanups. Removed code for many old, unsupported systems:
	- Atari
	- Amiga
	- BeOS
	- Cray
	- MIPS RiscOS
	- MS-DOS with Microsoft Compiler
	- MS-Windows with Microsoft Compiler
	- NeXT
	- SunOS 3.x, Sun 386 (Road Runner)
	- Tandem (non-POSIX)
	- Prestandard VAX C compiler for VAX/VMS
	- Probably others that I've forgotten

29. If PROCINFO["sorted_in"] exists, for(iggy in foo) loops sort the
    indices before looping over them.  The value of this element
    provides control over how the indices are sorted before the loop
    traversal starts. See the manual.

30. A new isarray() function exists to distinguish if an item is an array
    or not, to make it possible to traverse multidimensional arrays.

31. asort() and asorti() take a third argument specifying how to sort.
    See the doc.
