m4/ax_check_gnu_make.m4

   1 # ===========================================================================
   2 #     http://www.gnu.org/software/autoconf-archive/ax_check_gnu_make.html
   3 # ===========================================================================
   4 #
   5 # SYNOPSIS
   6 #
   7 #   AX_CHECK_GNU_MAKE()
   8 #
   9 # DESCRIPTION
  10 #
  11 #   This macro searches for a GNU version of make. If a match is found, the
  12 #   makefile variable `ifGNUmake' is set to the empty string, otherwise it
  13 #   is set to "#". This is useful for including a special features in a
  14 #   Makefile, which cannot be handled by other versions of make. The
  15 #   variable _cv_gnu_make_command is set to the command to invoke GNU make
  16 #   if it exists, the empty string otherwise.
  17 #
  18 #   Here is an example of its use:
  19 #
  20 #   Makefile.in might contain:
  21 #
  22 #     # A failsafe way of putting a dependency rule into a makefile
  23 #     $(DEPEND):
  24 #             $(CC) -MM $(srcdir)/*.c > $(DEPEND)
  25 #
  26 #     @ifGNUmake@ ifeq ($(DEPEND),$(wildcard $(DEPEND)))
  27 #     @ifGNUmake@ include $(DEPEND)
  28 #     @ifGNUmake@ endif
  29 #
  30 #   Then configure.in would normally contain:
  31 #
  32 #     AX_CHECK_GNU_MAKE()
  33 #     AC_OUTPUT(Makefile)
  34 #
  35 #   Then perhaps to cause gnu make to override any other make, we could do
  36 #   something like this (note that GNU make always looks for GNUmakefile
  37 #   first):
  38 #
  39 #     if  ! test x$_cv_gnu_make_command = x ; then
  40 #             mv Makefile GNUmakefile
  41 #             echo .DEFAULT: > Makefile ;
  42 #             echo \  $_cv_gnu_make_command \$@ >> Makefile;
  43 #     fi
  44 #
  45 #   Then, if any (well almost any) other make is called, and GNU make also
  46 #   exists, then the other make wraps the GNU make.
  47 #
  48 # LICENSE
  49 #
  50 #   Copyright (c) 2008 John Darrington <j.darrington@elvis.murdoch.edu.au>
  51 #
  52 #   Copying and distribution of this file, with or without modification, are
  53 #   permitted in any medium without royalty provided the copyright notice
  54 #   and this notice are preserved. This file is offered as-is, without any
  55 #   warranty.
  56
  57 #serial 7
  58
  59 AC_DEFUN([AX_CHECK_GNU_MAKE], [ AC_CACHE_CHECK( for GNU make,_cv_gnu_make_command,
  60                 _cv_gnu_make_command='' ;
  61 dnl Search all the common names for GNU make
  62                 for a in "$MAKE" make gmake gnumake ; do
  63                         if test -z "$a" ; then continue ; fi ;
  64                         if  ( sh -c "$a --version" 2> /dev/null | grep GNU  2>&1 > /dev/null ) ;  then
  65                                 _cv_gnu_make_command=$a ;
  66                                 break;
  67                         fi
  68                 done ;
  69         ) ;
  70 dnl If there was a GNU version, then set @ifGNUmake@ to the empty string, '#' otherwise
  71         if test  "x$_cv_gnu_make_command" != "x"  ; then
  72                 ifGNUmake='' ;
  73         else
  74                 ifGNUmake='#' ;
  75                 AC_MSG_RESULT("Not found");
  76         fi
  77         AC_SUBST(ifGNUmake)
  78 ] )