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 \ $_cv_gnu_make_command \$@ >> Makefile; 57# fi 58# 59# Then, if any (well almost any) other make is called, and GNU make also 60# exists, then the other make wraps the GNU make. 61# 62# LICENSE 63# 64# Copyright (c) 2008 John Darrington <j.darrington@elvis.murdoch.edu.au> 65# Copyright (c) 2015 Enrico M. Crisostomo <enrico.m.crisostomo@gmail.com> 66# 67# Copying and distribution of this file, with or without modification, are 68# permitted in any medium without royalty provided the copyright notice 69# and this notice are preserved. This file is offered as-is, without any 70# warranty. 71 72#serial 12 73 74AC_DEFUN([AX_CHECK_GNU_MAKE],dnl 75 [AC_PROG_AWK 76 AC_CACHE_CHECK([for GNU make],[_cv_gnu_make_command],[dnl 77 _cv_gnu_make_command="" ; 78dnl Search all the common names for GNU make 79 for a in "$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 $(NF); }') 85 break ; 86 fi 87 done ;]) 88dnl If there was a GNU version, then set @ifGNUmake@ to the empty string, '#' otherwise 89 AS_VAR_IF([_cv_gnu_make_command], [""], [AS_VAR_SET([ifGNUmake], ["#"])], [AS_VAR_SET([ifGNUmake], [""])]) 90 AS_VAR_IF([_cv_gnu_make_command], [""], [AS_VAR_SET([ifnGNUmake], [""])], [AS_VAR_SET([ifnGNUmake], ["#"])]) 91 AS_VAR_IF([_cv_gnu_make_command], [""], [AS_UNSET(ax_cv_gnu_make_command)], [AS_VAR_SET([ax_cv_gnu_make_command], [${_cv_gnu_make_command}])]) 92 AS_VAR_IF([_cv_gnu_make_command], [""],[$2],[$1]) 93 AC_SUBST([ifGNUmake]) 94 AC_SUBST([ifnGNUmake]) 95]) 96