1# =========================================================================== 2# https://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 \ $_cv_gnu_make_command \$@ >> Makefile; 49# fi 50# 51# Then, if any (well almost any) other make is called, and GNU make also 52# exists, then the other make wraps the GNU make. 53# 54# LICENSE 55# 56# Copyright (c) 2008 John Darrington <j.darrington@elvis.murdoch.edu.au> 57# Copyright (c) 2015 Enrico M. Crisostomo <enrico.m.crisostomo@gmail.com> 58# 59# Copying and distribution of this file, with or without modification, are 60# permitted in any medium without royalty provided the copyright notice 61# and this notice are preserved. This file is offered as-is, without any 62# warranty. 63 64#serial 9 65 66AC_DEFUN([AX_CHECK_GNU_MAKE],dnl 67 [AC_PROG_AWK 68 AC_CACHE_CHECK([for GNU make],[_cv_gnu_make_command],[dnl 69 _cv_gnu_make_command="" ; 70dnl Search all the common names for GNU make 71 for a in "$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 $(NF); }') 77 break ; 78 fi 79 done ;]) 80dnl If there was a GNU version, then set @ifGNUmake@ to the empty string, '#' otherwise 81 AS_VAR_IF([_cv_gnu_make_command], [""], [AS_VAR_SET([ifGNUmake], ["#"])], [AS_VAR_SET([ifGNUmake], [""])]) 82 AS_VAR_IF([_cv_gnu_make_command], [""], [AS_UNSET(ax_cv_gnu_make_command)], [AS_VAR_SET([ax_cv_gnu_make_command], [${_cv_gnu_make_command}])]) 83 AC_SUBST([ifGNUmake]) 84]) 85