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-rw-r--r--gnu/dist/diffutils/m4/gnu-source.m425
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diff --git a/gnu/dist/diffutils/m4/gnu-source.m4 b/gnu/dist/diffutils/m4/gnu-source.m4
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+#serial 3
+# Make sure _GNU_SOURCE is defined where necessary: as early as possible
+# for configure-time tests, as well as for every source file that includes
+# config.h.
+
+# From Jim Meyering.
+
+AC_DEFUN([AC__GNU_SOURCE],
+[
+ # Make sure that _GNU_SOURCE is defined for all subsequent
+ # configure-time compile tests.
+ # This definition must be emitted (into confdefs.h) before any
+ # test that involves compilation.
+ cat >>confdefs.h <<\EOF
+#ifndef _GNU_SOURCE
+# define _GNU_SOURCE
+#endif
+EOF
+
+ # Emit this code into config.h.in.
+ # The ifndef is to avoid redefinition warnings.
+ AH_VERBATIM([_GNU_SOURCE], [#ifndef _GNU_SOURCE
+# define _GNU_SOURCE
+#endif])
+])