This is a port of Lib PNG 1.5.10 to MSDOS/DJGPP.

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

        This port uses the newest snprintf version from the DJGPP repository.
        There are no other djgpp specific changes to the sources.  Only the
        usual configuration files have been added.  They are located in the
        /djgpp directory.  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 or
        WINDOWS OS if the stream comes from 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 to become familiar with the products.


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 png1510b.zip      or
          djtarx png1510b.zip       or
          pkunzip -d png1510b.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 png1510s.zip      or
          djtarx png1510s.zip       or
          pkunzip -d png1510s.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,
          gwkNNNb.zip, mktmpNNb.zip and zlibNNN.zip

        If you want to run the check you will need also:
          difNNNb.zip and gwkNNNb.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.:   The package has been configured for both DJGPP 2.03 and DJGPP 2.04.
        There is a separate build directory for DJGPP 2.03 and for DJGPP 2.04
        under the top srcdir (aka libpng-1.510).  To build the binaries
        using the 2.03 version of DJGPP cd into _build.203; if you prefer to
        build the binaries using DJGPP 2.04 cd into _build.204.  If for some
        reason you want to reconfigure the package cd into the corresponding
        build directory and run the following commands:
          make distclean
          ..\djgpp\config ./..

        Please note that you *MUST* delete the config.cache file in the build
        directory or you will not really reconfigure the sources because the
        configuration informations will be read from the cache file instead
        of being newly computed.

        config.bat, among other things, will start the configure script passing
        to it a couple of arguments.  All other configure specific options are
        not set by config.bat so their values are left as they are.  If no
        arguments are passed to config.bat then the default values are used.

        To build the programs in a directory on a disk or partition other than
        where the sources are, you must add the parameter that specifies the
        source directory, e.g:
          x:\src\contrib\libpng-1.510\djgpp\config x:/src/contrib/libpng-1.510

        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-1.510\djgpp\config x:/src/contrib/libpng-1.510

        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 Lib PNG 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>
