source: kBuild/vendor/gnumake/3.81-beta1/README.OS2

Port of GNU make to OS/2.

Features of GNU make that do not work under OS/2:
  - remote job execution
  - dynamic load balancing


Special features of the OS/2 version:

Due to the fact that some people might want to use sh syntax in
Makefiles while others might want to use OS/2's native shell cmd.exe,
GNU make supports both shell types. The following list defines the order
that is used to determine the shell:

 1. The shell specified by the environment variable MAKESHELL.
 2. The shell specified by the SHELL variable within a Makefile. As on
    Unix, SHELL is NOT taken from the environment.
 3. The shell specified by the COMSPEC environment variable.
 4. The shell specified by the OS2_SHELL environment variable.
 5. If none of the above is defined /bin/sh is used as default.  This
    happens e.g. in the make testsuite.

Note: - Points 3 and 4 can be turned off at compile time by adding
        -DNO_CMD_DEFAULT to the CPPFLAGS.
      - DOS support is not tested for EMX and therefore might not work.
      - The UNIXROOT environment variable is supported to find /bin/sh
        if it is not on the current drive.


COMPILATION OF GNU MAKE FOR OS/2:

I. ***** SPECIAL OPTIONS *****

 - At compile time you can turn off that cmd is used as default shell
   (but only /bin/sh). Simply set CPPFLAGS="-DNO_CMD_DEFAULT" and make
   will not use cmd unless you cause it to do so by setting MAKESHELL to
   cmd or by specifying SHELL=cmd in your Makefile.

 - At compile time you can set CPPFLAGS="-DNO_CHDIR2" to turn off that
   GNU make prints drive letters. This is necessary if you want to run
   the testsuite.


II. ***** REQUIREMENTS FOR THE COMPILATION *****

A standard Unix like build environment:

 - sh compatible shell (ksh, bash, ash, but tested only with pdksh 5.2.14
   (release 2)
   If you use pdksh it is recommended to update to 5.2.14 release 2. Older
   versions may not work! You can get this version at
   http://www.math.ohio-state.edu/~ilya/software/os2/pdksh-5.2.14-bin-2.zip
 - GNU file utilities (make sure that install.exe from the file utilities
   is in front of your PATH before X:\OS2\INSTALL\INSTALL.EXE. I recommend
   also to change the filename to ginstall.exe instead of install.exe
   to avoid confusion with X:\OS2\INSTALL\INSTALL.EXE)
 - GNU shell utilities
 - GNU text utilities
 - gawk
 - grep
 - sed
 - GNU make 3.79.1 (special OS/2 patched version)
 - perl 5.005 or higher
 - GNU texinfo (you can use 3.1 (gnuinfo.zip), but I recommend 4.0)

If you want to recreate the configuration files (developers only!)
you need also: GNU m4 1.4, autoconf 2.57, automake 1.7.2 (or compatible)


III. ***** COMPILATION AND INSTALLATION *****

 a) ** Developers only - Everyone else should skip this section **
    To recreate the configuration files use:

      export EMXSHELL=ksh
      aclocal -I config
      automake
      autoconf
      autoheader


b) Installation into x:/usr

   Note: Although it is possible to compile make using "./configure",
         "make", "make install" this is not recommended.  In particular,
         you must ALWAYS use LDFLAGS="-Zstack 0x8000" because the default
         stack size is far to small and make will not work properly!

Recommended environment variables and installation options:

    export ac_executable_extensions=".exe"
    export CPPFLAGS="-D__ST_MT_ERRNO__"
    export CFLAGS="-O2 -Zomf -Zmt"
    export LDFLAGS="-Zcrtdll -Zlinker /exepack:2 -Zlinker /pm:vio -Zstack 0x8000"
    export RANLIB="echo"
    ./configure --prefix=x:/usr --infodir=x:/usr/share/info --mandir=x:/usr/share/man --without-included-gettext
    make AR=emxomfar
    make install

Note: If you use gcc 2.9.x or higher I recommend to set also LIBS="-lgcc"

Note: You can add -DNO_CMD_DEFAULT and -DNO_CHDIR2 to CPPFLAGS.
      See section I. for details.


IV. ***** NLS support *****

GNU make has NLS (National Language Support), with the following
caveats:

 a) It will only work with GNU gettext, and
 b) GNU gettext support is not included in the GNU make package.

Therefore, if you wish to enable the internationalization features of
GNU make you must install GNU gettext on your system before configuring
GNU make.

You can choose the languages to be installed. To install support for
English, German and French only enter:

  export LINGUAS="en de fr"

If you don't specify LINGUAS all languages are installed.

If you don't want NLS support (English only) use the option
--disable-nls for the configure script.  Note if GNU gettext is not
installed then NLS will not be enabled regardless of this flag.


V. ***** Running the make test suite *****

To run the included make test suite you have to set

  CPPFLAGS="-D__ST_MT_ERRNO__ -DNO_CMD_DEFAULT -DNO_CHDIR2"

before you compile make. This is due to some restrictions of the
testsuite itself. -DNO_CMD_DEFAULT causes make to use /bin/sh as default
shell in every case. Normally you could simply set MAKESHELL="/bin/sh"
to do this but the testsuite ignores the environment. -DNO_CHDIR2 causes
make not to use drive letters for directory names (i.e. _chdir2() and
_getcwd2() are NOT used).  The testsuite interpretes the whole output of
make, especially statements like make[1]: Entering directory
`C:/somewhere/make-3.79.1/tests' where the testsuite does not expect the
drive letter. This would be interpreted as an error even if there is
none.

To run the testsuite do the following:

  export CPPFLAGS="-D__ST_MT_ERRNO__ -DNO_CMD_DEFAULT -DNO_CHDIR2"
  export CFLAGS="-Zomf -O2 -s -Zmt"
  export LDFLAGS="-Zcrtdll -Zmt -s -Zlinker /exepack:2 -Zlinker /pm:vio -Zstack 0x8000"
  export RANLIB="echo"
  ./configure --prefix=x:/usr --disable-nls
  make AR=emxomfar
  make checks

All tests should work fine with the exception of "default_names" which
is because OS/2 file systems are not case sensitive ("makefile" and
"Makefile" specify the same file).