This is a port of libpng 1.2.20 to MSDOS/DJGPP.

1.:     DJGPP specific changes.
        =======================

        There are no djgpp specific changes to the sources. Only the usual
        configuration files have been added. They are located in the /djgpp
        subdir.  As for all binaries and libraries that handle images of any
        kind, it should be noticed that files (streams) are *always* openend
        in binary mode with all the well known implications on a DOS/WINDOWS
        OS if the stream is connected to STDIN and/or STDOUT when these are
        still connected to the console.

        To use and compile from sources this library you will have to install
        the zlib library.
          
        Please *read* the docs.


2.:     Installing the binary package.
        ==============================

2.1.:   Copy the binary distribution into the top DJGPP installation directory,
        just unzip it preserving the directory structure running *ONE* of the
        following commands:
          unzip32 png1220b.zip      or
          djtarx png1220b.zip       or
          pkunzip -d png1220b.zip



3.:     Building the binaries from sources.
        ===================================

3.1.:   Create a temporary directory and copy the source package into the
        directory.  If you download the source distribution from one of the
        DJGPP sites, just unzip it preserving the directory structure
        running *ONE* of the following commands:
          unzip32 png1220s.zip      or
          djtarx png1220s.zip       or
          pkunzip -d png1220s.zip

3.2.:   To build the binaries you will need the following binary packages:
          djdev203.zip (or a later but NOT a prior version)
          bsh204b.zip  (or a later but NOT a prior version)
          gccNNNb.zip, gppNNN.zip, bnuNNNb.zip, makNNNb.zip, filNNNb.zip,
          shlNNNb.zip, txtNNNb.zip, txiNNNb.zip, grepNNNb.zip, sedNNNb.zip,
          and m4NNN.zip

        If you want to run the check you will need also:
          difNNNb.zip

        NNN represents the latest version number of the binary packages.
        All these packages can be found in the /v2gnu directory of any
        ftp.delorie.com mirror.
        You will need bsh204b.zip or later and *NOT* a prior version or
        the build will fail.  The same applies to djdev203.zip.

3.3.:   If for some reason you want to reconfigure the package cd into the top
        srcdir (libpng-1.220) and run the following commands:
          del djgpp\config.cache
          make clean
          djgpp\config

        Please note that you *MUST* delete the config.cache file in the djgpp
        subdir or you will not really reconfigure the sources because the
        configuration informations will be read from the cache file instead
        of being newly computed.
        To build the programs in a directory other than where the sources are,
        you must add the parameter that specifies the source directory,
        e.g:
          x:\src\contrib\libpng-1.220\djgpp\config x:/src/contrib/libpng-1.220

        Lets assume you want to build the binaries in a directory placed on a
        different drive (z:\build in this case) from where the sources are,
        then you will run the following commands:
          z:
          md \build
          cd \build
          x:\src\contrib\libpng-1.220\djgpp\config x:/src/contrib/libpng-1.220

        The order of the options and the srcdir option does not matter.  You
        *MUST* use forward slashes to specify the source directory.

        The batch file will set same environment variables, make MSDOS specific
        modifications to the Makefile.in's and supply all other needed options
        to the configure script.

3.4.:   To compile the package run from the top srcdir the command:
          make

3.5.:   Now you can run the tests if you like.  From the top srcdir run the
        command:
          make check

        No test should fail.

3.6.:   To install the binaries, header, library, catalogs, and info docs
        run the following command from the top srcdir:
          make install

        This will install the products into your DJGPP installation tree given
        by the default prefix "/dev/env/DJDIR".  If you prefer to install them
        into some other directory you will have to set prefix to the appropiate
        value:
          make install prefix=z:/some/other/place



        Send libpng specific bug reports to <glennrp@users.sourceforge.net>.
        Send suggestions and bug reports concerning the DJGPP port to
        comp.os.msdos.djgpp or <djgpp@delorie.com>.


Enjoy.

        Guerrero, Juan Manuel <juan.guerrero@gmx.de>
