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: 12 # 13 # * The makefile variable `ifGNUmake' is set to the empty string, otherwise 14 # it is set to "#". This is useful for including a special features in a 15 # Makefile, which cannot be handled by other versions of make. 16 # * The variable `_cv_gnu_make_command` is set to the command to invoke 17 # GNU make if it exists, the empty string otherwise. 18 # * The variable `ax_cv_gnu_make_command` is set to the command to invoke 19 # GNU make by copying `_cv_gnu_make_command`, otherwise it is unset. 20 # * If GNU Make is found, its version is extracted from the output of 21 # `make --version` as the last field of a record of space-separated 22 # columns and saved into the variable `ax_check_gnu_make_version`. 23 # 24 # Here is an example of its use: 25 # 26 # Makefile.in might contain: 27 # 28 # # A failsafe way of putting a dependency rule into a makefile 29 # $(DEPEND): 30 # $(CC) -MM $(srcdir)/*.c > $(DEPEND) 31 # 32 # @ifGNUmake@ ifeq ($(DEPEND),$(wildcard $(DEPEND))) 33 # @ifGNUmake@ include $(DEPEND) 34 # @ifGNUmake@ endif 35 # 36 # Then configure.in would normally contain: 37 # 38 # AX_CHECK_GNU_MAKE() 39 # AC_OUTPUT(Makefile) 40 # 41 # Then perhaps to cause gnu make to override any other make, we could do 42 # something like this (note that GNU make always looks for GNUmakefile 43 # first): 44 # 45 # if ! test x$_cv_gnu_make_command = x ; then 46 # mv Makefile GNUmakefile 47 # echo .DEFAULT: > Makefile ; 48 # echo \ $_cv_gnu_make_command \$@ >> Makefile; 49 # fi 50 # 51 # Then, if any (well almost any) other make is called, and GNU make also 52 # exists, then the other make wraps the GNU make. 53 # 54 # LICENSE 55 # 56 # Copyright (c) 2008 John Darrington <j.darrington@elvis.murdoch.edu.au> 57 # Copyright (c) 2015 Enrico M. Crisostomo <enrico.m.crisostomo@gmail.com> 58 # 59 # Copying and distribution of this file, with or without modification, are 60 # permitted in any medium without royalty provided the copyright notice 61 # and this notice are preserved. This file is offered as-is, without any 62 # warranty. 63 64 #serial 8 65 66 AC_DEFUN([AX_CHECK_GNU_MAKE],dnl 67 [AC_PROG_AWK 68 AC_CACHE_CHECK([for GNU make],[_cv_gnu_make_command],[dnl 69 _cv_gnu_make_command="" ; 70 dnl Search all the common names for GNU make 71 for a in "$MAKE" make gmake gnumake ; do 72 if test -z "$a" ; then continue ; fi ; 73 if "$a" --version 2> /dev/null | grep GNU 2>&1 > /dev/null ; then 74 _cv_gnu_make_command=$a ; 75 AX_CHECK_GNU_MAKE_HEADLINE=$("$a" --version 2> /dev/null | grep "GNU Make") 76 ax_check_gnu_make_version=$(echo ${AX_CHECK_GNU_MAKE_HEADLINE} | ${AWK} -F " " '{ print $(NF); }') 77 break ; 78 fi 79 done ;]) 80 dnl If there was a GNU version, then set @ifGNUmake@ to the empty string, '#' otherwise 81 AS_VAR_IF([_cv_gnu_make_command], [""], [AS_VAR_SET([ifGNUmake], ["#"])], [AS_VAR_SET([ifGNUmake], [""])]) 82 AS_VAR_IF([_cv_gnu_make_command], [""], [AS_UNSET(ax_cv_gnu_make_command)], [AS_VAR_SET([ax_cv_gnu_make_command], [${_cv_gnu_make_command}])]) 83 AC_SUBST([ifGNUmake]) 84 ])
