ax_check_gnu_make.m4 (4055B)
1 # =========================================================================== 2 # https://www.gnu.org/software/autoconf-archive/ax_check_gnu_make.html 3 # =========================================================================== 4 # 5 # SYNOPSIS 6 # 7 # AX_CHECK_GNU_MAKE([run-if-true],[run-if-false]) 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 makefile variable `ifnGNUmake' is set to #, otherwise 17 # it is set to the empty string. This is useful for including a special 18 # features in a Makefile, which can be handled 19 # by other versions of make or to specify else like clause. 20 # * The variable `_cv_gnu_make_command` is set to the command to invoke 21 # GNU make if it exists, the empty string otherwise. 22 # * The variable `ax_cv_gnu_make_command` is set to the command to invoke 23 # GNU make by copying `_cv_gnu_make_command`, otherwise it is unset. 24 # * If GNU Make is found, its version is extracted from the output of 25 # `make --version` as the last field of a record of space-separated 26 # columns and saved into the variable `ax_check_gnu_make_version`. 27 # * Additionally if GNU Make is found, run shell code run-if-true 28 # else run shell code run-if-false. 29 # 30 # Here is an example of its use: 31 # 32 # Makefile.in might contain: 33 # 34 # # A failsafe way of putting a dependency rule into a makefile 35 # $(DEPEND): 36 # $(CC) -MM $(srcdir)/*.c > $(DEPEND) 37 # 38 # @ifGNUmake@ ifeq ($(DEPEND),$(wildcard $(DEPEND))) 39 # @ifGNUmake@ include $(DEPEND) 40 # @ifGNUmake@ else 41 # fallback code 42 # @ifGNUmake@ endif 43 # 44 # Then configure.in would normally contain: 45 # 46 # AX_CHECK_GNU_MAKE() 47 # AC_OUTPUT(Makefile) 48 # 49 # Then perhaps to cause gnu make to override any other make, we could do 50 # something like this (note that GNU make always looks for GNUmakefile 51 # first): 52 # 53 # if ! test x$_cv_gnu_make_command = x ; then 54 # mv Makefile GNUmakefile 55 # echo .DEFAULT: > Makefile ; 56 # echo \ $_cv_gnu_make_command \$@ >> Makefile; 57 # fi 58 # 59 # Then, if any (well almost any) other make is called, and GNU make also 60 # exists, then the other make wraps the GNU make. 61 # 62 # LICENSE 63 # 64 # Copyright (c) 2008 John Darrington <j.darrington@elvis.murdoch.edu.au> 65 # Copyright (c) 2015 Enrico M. Crisostomo <enrico.m.crisostomo@gmail.com> 66 # 67 # Copying and distribution of this file, with or without modification, are 68 # permitted in any medium without royalty provided the copyright notice 69 # and this notice are preserved. This file is offered as-is, without any 70 # warranty. 71 72 #serial 12 73 74 AC_DEFUN([AX_CHECK_GNU_MAKE],dnl 75 [AC_PROG_AWK 76 AC_CACHE_CHECK([for GNU make],[_cv_gnu_make_command],[dnl 77 _cv_gnu_make_command="" ; 78 dnl Search all the common names for GNU make 79 for a in "$MAKE" make gmake gnumake ; do 80 if test -z "$a" ; then continue ; fi ; 81 if "$a" --version 2> /dev/null | grep GNU 2>&1 > /dev/null ; then 82 _cv_gnu_make_command=$a ; 83 AX_CHECK_GNU_MAKE_HEADLINE=$("$a" --version 2> /dev/null | grep "GNU Make") 84 ax_check_gnu_make_version=$(echo ${AX_CHECK_GNU_MAKE_HEADLINE} | ${AWK} -F " " '{ print $(NF); }') 85 break ; 86 fi 87 done ;]) 88 dnl If there was a GNU version, then set @ifGNUmake@ to the empty string, '#' otherwise 89 AS_VAR_IF([_cv_gnu_make_command], [""], [AS_VAR_SET([ifGNUmake], ["#"])], [AS_VAR_SET([ifGNUmake], [""])]) 90 AS_VAR_IF([_cv_gnu_make_command], [""], [AS_VAR_SET([ifnGNUmake], [""])], [AS_VAR_SET([ifnGNUmake], ["#"])]) 91 AS_VAR_IF([_cv_gnu_make_command], [""], [AS_UNSET(ax_cv_gnu_make_command)], [AS_VAR_SET([ax_cv_gnu_make_command], [${_cv_gnu_make_command}])]) 92 AS_VAR_IF([_cv_gnu_make_command], [""],[$2],[$1]) 93 AC_SUBST([ifGNUmake]) 94 AC_SUBST([ifnGNUmake]) 95 ])