Building XZ Utils for DOS
=========================

Introduction

    This document explains how to build XZ Utils for DOS using DJGPP.
    The resulting binaries should run at least on various DOS versions
    and under Windows 95/98/98SE/ME.

    This is somewhat experimental and has got very little testing.

    Note: Makefile and config.h are updated only now and then. This
    means that if you checked out a development version, building for
    DOS might not work without updating Makefile and config.h first.


Getting and Installing DJGPP

    You may use <https://www.delorie.com/djgpp/zip-picker.html> to help
    deciding what to download. If you are only interested in building
    XZ Utils, the zip-picker may list files that you don't strictly
    need. However, using the zip-picker can still be worth it to get a
    nice short summary of installation instructions (they can be found
    from readme.1st too).

    For a more manual method, first select a mirror from
    <https://www.delorie.com/djgpp/getting.html> and go the
    subdirectory named "current". You need the following files:

        unzip32.exe  (if you don't already have a LFN-capable unzipper)
        v2/djdev205.zip
        v2gnu/bnu234b.zip
        v2gnu/gcc920b.zip
        v2gnu/mak43b.zip
        v2misc/csdpmi7b.zip

    If newer versions are available, probably you should try them first.
    Note that versions older than djdev205.zip aren't supported. Also
    note that you want csdpmi7b.zip even if you run under Windows or
    DOSEMU because the XZ Utils Makefile will embed cwsdstub.exe to
    the resulting xz.exe.

    See the instructions in readme.1st found from djdev205.zip. Here's
    a short summary, but you should still read readme.1st.

        C:\> mkdir DJGPP
        C:\> cd DJGPP
        C:\DJGPP> c:\download\unzip32 c:\download\djdev205.zip
        C:\DJGPP> c:\download\unzip32 c:\download\bnu234b.zip
        C:\DJGPP> c:\download\unzip32 c:\download\gcc920b.zip
        C:\DJGPP> c:\download\unzip32 c:\download\mak43b.zip
        C:\DJGPP> c:\download\unzip32 c:\download\csdpmi7b.zip

        C:\DJGPP> set PATH=C:\DJGPP\BIN;%PATH%
        C:\DJGPP> set DJGPP=C:\DJGPP\DJGPP.ENV

    You may want to add the last two lines into AUTOEXEC.BAT or have,
    for example, DJGPP.BAT which you can run before using DJGPP.

    Make sure you use completely upper case path in the DJGPP environment
    variable. This is not required by DJGPP, but the XZ Utils Makefile is
    a bit stupid and expects that everything in DJGPP environment variable
    is uppercase.


Building

    You need to have an environment that supports long filenames (LFN).
    Once you have built XZ Utils, the resulting binaries can be run
    without long filename support.

    Run "make" in this directory (the directory containing this
    INSTALL.txt). You should get xz.exe (and a bunch of temporary files).
    Other tools are not built. Having e.g. xzdec.exe doesn't save much
    space compared to xz.exe because the DJGPP runtime makes the .exe
    quite big anyway.