xref: /freebsd/sys/contrib/libsodium/m4/ax_check_gnu_make.m4 (revision 3611ec604864a7d4dcc9a3ea898c80eb35eef8a0)
1*0ac341f1SConrad Meyer# ===========================================================================
2*0ac341f1SConrad Meyer#    https://www.gnu.org/software/autoconf-archive/ax_check_gnu_make.html
3*0ac341f1SConrad Meyer# ===========================================================================
4*0ac341f1SConrad Meyer#
5*0ac341f1SConrad Meyer# SYNOPSIS
6*0ac341f1SConrad Meyer#
7*0ac341f1SConrad Meyer#   AX_CHECK_GNU_MAKE()
8*0ac341f1SConrad Meyer#
9*0ac341f1SConrad Meyer# DESCRIPTION
10*0ac341f1SConrad Meyer#
11*0ac341f1SConrad Meyer#   This macro searches for a GNU version of make. If a match is found:
12*0ac341f1SConrad Meyer#
13*0ac341f1SConrad Meyer#     * The makefile variable `ifGNUmake' is set to the empty string, otherwise
14*0ac341f1SConrad Meyer#       it is set to "#". This is useful for including a special features in a
15*0ac341f1SConrad Meyer#       Makefile, which cannot be handled by other versions of make.
16*0ac341f1SConrad Meyer#     * The variable `_cv_gnu_make_command` is set to the command to invoke
17*0ac341f1SConrad Meyer#       GNU make if it exists, the empty string otherwise.
18*0ac341f1SConrad Meyer#     * The variable `ax_cv_gnu_make_command` is set to the command to invoke
19*0ac341f1SConrad Meyer#       GNU make by copying `_cv_gnu_make_command`, otherwise it is unset.
20*0ac341f1SConrad Meyer#     * If GNU Make is found, its version is extracted from the output of
21*0ac341f1SConrad Meyer#       `make --version` as the last field of a record of space-separated
22*0ac341f1SConrad Meyer#       columns and saved into the variable `ax_check_gnu_make_version`.
23*0ac341f1SConrad Meyer#
24*0ac341f1SConrad Meyer#   Here is an example of its use:
25*0ac341f1SConrad Meyer#
26*0ac341f1SConrad Meyer#   Makefile.in might contain:
27*0ac341f1SConrad Meyer#
28*0ac341f1SConrad Meyer#     # A failsafe way of putting a dependency rule into a makefile
29*0ac341f1SConrad Meyer#     $(DEPEND):
30*0ac341f1SConrad Meyer#             $(CC) -MM $(srcdir)/*.c > $(DEPEND)
31*0ac341f1SConrad Meyer#
32*0ac341f1SConrad Meyer#     @ifGNUmake@ ifeq ($(DEPEND),$(wildcard $(DEPEND)))
33*0ac341f1SConrad Meyer#     @ifGNUmake@ include $(DEPEND)
34*0ac341f1SConrad Meyer#     @ifGNUmake@ endif
35*0ac341f1SConrad Meyer#
36*0ac341f1SConrad Meyer#   Then configure.in would normally contain:
37*0ac341f1SConrad Meyer#
38*0ac341f1SConrad Meyer#     AX_CHECK_GNU_MAKE()
39*0ac341f1SConrad Meyer#     AC_OUTPUT(Makefile)
40*0ac341f1SConrad Meyer#
41*0ac341f1SConrad Meyer#   Then perhaps to cause gnu make to override any other make, we could do
42*0ac341f1SConrad Meyer#   something like this (note that GNU make always looks for GNUmakefile
43*0ac341f1SConrad Meyer#   first):
44*0ac341f1SConrad Meyer#
45*0ac341f1SConrad Meyer#     if  ! test x$_cv_gnu_make_command = x ; then
46*0ac341f1SConrad Meyer#             mv Makefile GNUmakefile
47*0ac341f1SConrad Meyer#             echo .DEFAULT: > Makefile ;
48*0ac341f1SConrad Meyer#             echo \  $_cv_gnu_make_command \$@ >> Makefile;
49*0ac341f1SConrad Meyer#     fi
50*0ac341f1SConrad Meyer#
51*0ac341f1SConrad Meyer#   Then, if any (well almost any) other make is called, and GNU make also
52*0ac341f1SConrad Meyer#   exists, then the other make wraps the GNU make.
53*0ac341f1SConrad Meyer#
54*0ac341f1SConrad Meyer# LICENSE
55*0ac341f1SConrad Meyer#
56*0ac341f1SConrad Meyer#   Copyright (c) 2008 John Darrington <j.darrington@elvis.murdoch.edu.au>
57*0ac341f1SConrad Meyer#   Copyright (c) 2015 Enrico M. Crisostomo <enrico.m.crisostomo@gmail.com>
58*0ac341f1SConrad Meyer#
59*0ac341f1SConrad Meyer#   Copying and distribution of this file, with or without modification, are
60*0ac341f1SConrad Meyer#   permitted in any medium without royalty provided the copyright notice
61*0ac341f1SConrad Meyer#   and this notice are preserved. This file is offered as-is, without any
62*0ac341f1SConrad Meyer#   warranty.
63*0ac341f1SConrad Meyer
64*0ac341f1SConrad Meyer#serial 9
65*0ac341f1SConrad Meyer
66*0ac341f1SConrad MeyerAC_DEFUN([AX_CHECK_GNU_MAKE],dnl
67*0ac341f1SConrad Meyer  [AC_PROG_AWK
68*0ac341f1SConrad Meyer  AC_CACHE_CHECK([for GNU make],[_cv_gnu_make_command],[dnl
69*0ac341f1SConrad Meyer    _cv_gnu_make_command="" ;
70*0ac341f1SConrad Meyerdnl Search all the common names for GNU make
71*0ac341f1SConrad Meyer    for a in "$MAKE" make gmake gnumake ; do
72*0ac341f1SConrad Meyer      if test -z "$a" ; then continue ; fi ;
73*0ac341f1SConrad Meyer      if "$a" --version 2> /dev/null | grep GNU 2>&1 > /dev/null ; then
74*0ac341f1SConrad Meyer        _cv_gnu_make_command=$a ;
75*0ac341f1SConrad Meyer        AX_CHECK_GNU_MAKE_HEADLINE=$("$a" --version 2> /dev/null | grep "GNU Make")
76*0ac341f1SConrad Meyer        ax_check_gnu_make_version=$(echo ${AX_CHECK_GNU_MAKE_HEADLINE} | ${AWK} -F " " '{ print $(NF); }')
77*0ac341f1SConrad Meyer        break ;
78*0ac341f1SConrad Meyer      fi
79*0ac341f1SConrad Meyer    done ;])
80*0ac341f1SConrad Meyerdnl If there was a GNU version, then set @ifGNUmake@ to the empty string, '#' otherwise
81*0ac341f1SConrad Meyer  AS_VAR_IF([_cv_gnu_make_command], [""], [AS_VAR_SET([ifGNUmake], ["#"])],   [AS_VAR_SET([ifGNUmake], [""])])
82*0ac341f1SConrad Meyer  AS_VAR_IF([_cv_gnu_make_command], [""], [AS_UNSET(ax_cv_gnu_make_command)], [AS_VAR_SET([ax_cv_gnu_make_command], [${_cv_gnu_make_command}])])
83*0ac341f1SConrad Meyer  AC_SUBST([ifGNUmake])
84*0ac341f1SConrad Meyer])
85