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Diffstat (limited to 'm4/ax_check_gnu_make.m4')
| -rw-r--r-- | m4/ax_check_gnu_make.m4 | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/m4/ax_check_gnu_make.m4 b/m4/ax_check_gnu_make.m4 new file mode 100644 index 0000000..785dc96 --- /dev/null +++ b/m4/ax_check_gnu_make.m4 @@ -0,0 +1,95 @@ +# =========================================================================== +# https://www.gnu.org/software/autoconf-archive/ax_check_gnu_make.html +# =========================================================================== +# +# SYNOPSIS +# +# AX_CHECK_GNU_MAKE([run-if-true],[run-if-false]) +# +# DESCRIPTION +# +# This macro searches for a GNU version of make. If a match is found: +# +# * The makefile variable `ifGNUmake' is set to the empty string, otherwise +# it is set to "#". This is useful for including a special features in a +# Makefile, which cannot be handled by other versions of make. +# * The makefile variable `ifnGNUmake' is set to #, otherwise +# it is set to the empty string. This is useful for including a special +# features in a Makefile, which can be handled +# by other versions of make or to specify else like clause. +# * The variable `_cv_gnu_make_command` is set to the command to invoke +# GNU make if it exists, the empty string otherwise. +# * The variable `ax_cv_gnu_make_command` is set to the command to invoke +# GNU make by copying `_cv_gnu_make_command`, otherwise it is unset. +# * If GNU Make is found, its version is extracted from the output of +# `make --version` as the last field of a record of space-separated +# columns and saved into the variable `ax_check_gnu_make_version`. +# * Additionally if GNU Make is found, run shell code run-if-true +# else run shell code run-if-false. +# +# Here is an example of its use: +# +# Makefile.in might contain: +# +# # A failsafe way of putting a dependency rule into a makefile +# $(DEPEND): +# $(CC) -MM $(srcdir)/*.c > $(DEPEND) +# +# @ifGNUmake@ ifeq ($(DEPEND),$(wildcard $(DEPEND))) +# @ifGNUmake@ include $(DEPEND) +# @ifGNUmake@ else +# fallback code +# @ifGNUmake@ endif +# +# Then configure.in would normally contain: +# +# AX_CHECK_GNU_MAKE() +# AC_OUTPUT(Makefile) +# +# Then perhaps to cause gnu make to override any other make, we could do +# something like this (note that GNU make always looks for GNUmakefile +# first): +# +# if ! test x$_cv_gnu_make_command = x ; then +# mv Makefile GNUmakefile +# echo .DEFAULT: > Makefile ; +# echo \ $_cv_gnu_make_command \$@ >> Makefile; +# fi +# +# Then, if any (well almost any) other make is called, and GNU make also +# exists, then the other make wraps the GNU make. +# +# LICENSE +# +# Copyright (c) 2008 John Darrington <j.darrington@elvis.murdoch.edu.au> +# Copyright (c) 2015 Enrico M. Crisostomo <enrico.m.crisostomo@gmail.com> +# +# Copying and distribution of this file, with or without modification, are +# permitted in any medium without royalty provided the copyright notice +# and this notice are preserved. This file is offered as-is, without any +# warranty. + +#serial 12 + +AC_DEFUN([AX_CHECK_GNU_MAKE],dnl + [AC_PROG_AWK + AC_CACHE_CHECK([for GNU make],[_cv_gnu_make_command],[dnl + _cv_gnu_make_command="" ; +dnl Search all the common names for GNU make + for a in "$MAKE" make gmake gnumake ; do + if test -z "$a" ; then continue ; fi ; + if "$a" --version 2> /dev/null | grep GNU 2>&1 > /dev/null ; then + _cv_gnu_make_command=$a ; + AX_CHECK_GNU_MAKE_HEADLINE=$("$a" --version 2> /dev/null | grep "GNU Make") + ax_check_gnu_make_version=$(echo ${AX_CHECK_GNU_MAKE_HEADLINE} | ${AWK} -F " " '{ print $(NF); }') + break ; + fi + done ;]) +dnl If there was a GNU version, then set @ifGNUmake@ to the empty string, '#' otherwise + AS_VAR_IF([_cv_gnu_make_command], [""], [AS_VAR_SET([ifGNUmake], ["#"])], [AS_VAR_SET([ifGNUmake], [""])]) + AS_VAR_IF([_cv_gnu_make_command], [""], [AS_VAR_SET([ifnGNUmake], [""])], [AS_VAR_SET([ifnGNUmake], ["#"])]) + AS_VAR_IF([_cv_gnu_make_command], [""], [AS_UNSET(ax_cv_gnu_make_command)], [AS_VAR_SET([ax_cv_gnu_make_command], [${_cv_gnu_make_command}])]) + AS_VAR_IF([_cv_gnu_make_command], [""],[$2],[$1]) + AC_SUBST([ifGNUmake]) + AC_SUBST([ifnGNUmake]) +]) |