xref: /netbsd-src/external/gpl2/diffutils/dist/m4/gnu-source.m4 (revision 75f6d617e282811cb173c2ccfbf5df0dd71f7045)
1#serial 3
2# Make sure _GNU_SOURCE is defined where necessary: as early as possible
3# for configure-time tests, as well as for every source file that includes
4# config.h.
5
6# From Jim Meyering.
7
8AC_DEFUN([AC__GNU_SOURCE],
9[
10  # Make sure that _GNU_SOURCE is defined for all subsequent
11  # configure-time compile tests.
12  # This definition must be emitted (into confdefs.h) before any
13  # test that involves compilation.
14  cat >>confdefs.h <<\EOF
15#ifndef _GNU_SOURCE
16# define _GNU_SOURCE
17#endif
18EOF
19
20  # Emit this code into config.h.in.
21  # The ifndef is to avoid redefinition warnings.
22  AH_VERBATIM([_GNU_SOURCE], [#ifndef _GNU_SOURCE
23# define _GNU_SOURCE
24#endif])
25])
26