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check_gnu_make

SYNOPSIS

CHECK_GNU_MAKE()

DESCRIPTION

This macro searches for a GNU version of make. If a match is found, the makefile variable `ifGNUmake' is set to the empty string, otherwise it is set to "#". This is useful for including a special features in a Makefile, which cannot be handled by other versions of make. The variable _cv_gnu_make_command is set to the command to invoke GNU make if it exists, the empty string otherwise.

Here is an example of its use:

Makefile.in might contain:

    # A failsafe way of putting a dependency rule into a makefile
    $(DEPEND):
            $(CC) -MM $(srcdir)/*.c > $(DEPEND)

    @ifGNUmake@ ifeq ($(DEPEND),$(wildcard $(DEPEND)))
    @ifGNUmake@ include $(DEPEND)
    @ifGNUmake@ endif

Then configure.in would normally contain:

    CHECK_GNU_MAKE()
    AC_OUTPUT(Makefile)

Then perhaps to cause gnu make to override any other make, we could do something like this (note that GNU make always looks for GNUmakefile first):

    if  ! test x$_cv_gnu_make_command = x ; then
            mv Makefile GNUmakefile
            echo .DEFAULT: > Makefile ;
            echo \  $_cv_gnu_make_command \$@ >> Makefile;
    fi

Then, if any (well almost any) other make is called, and GNU make also exists, then the other make wraps the GNU make.

SOURCE CODE

http://autoconf-archive.cryp.to/check_gnu_make.m4

LICENSE

Copyright © 2008 John Darrington <j.darrington@elvis.murdoch.edu.au>

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.