--- a
+++ b/aclocal.m4
@@ -0,0 +1,57 @@
+# Code swiped wholesale from the GCC project, see
+# http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12100
+
+# This file can go away once autoconf 2.58 is out and being used -
+# it's reported that this is fixed in the autoconf cvs already.
+
+# AC_LANG_FUNC_LINK_TRY(C)(FUNCTION)
+# ----------------------------------
+# Don't include <ctype.h> because on OSF/1 3.0 it includes
+# <sys/types.h> which includes <sys/select.h> which contains a
+# prototype for select.  Similarly for bzero.
+#
+# A similar problem afflicts HP/UX, but it also hits <sys/time.h>
+#
+# This test used to merely assign f=$1 in main(), but that was
+# optimized away by HP unbundled cc A.05.36 for ia64 under +O3,
+# presumably on the basis that there's no need to do that store if the
+# program is about to exit.  Conversely, the AIX linker optimizes an
+# unused external declaration that initializes f=$1.  So this test
+# program has both an external initialization of f, and a use of f in
+# main that affects the exit status.
+#
+m4_define([AC_LANG_FUNC_LINK_TRY(C)],
+[AC_LANG_PROGRAM(
+[/* System header to define __stub macros and hopefully few prototypes,
+    which can conflict with char $1 (); below.
+    Prefer <limits.h> to <assert.h> if __STDC__ is defined, since
+    <limits.h> exists even on freestanding compilers.  Under hpux,
+    including <limits.h> includes <sys/time.h> and causes problems
+    checking for functions defined therein.  */
+#if defined (__STDC__) && !defined (_HPUX_SOURCE)
+# include <limits.h>
+#else
+# include <assert.h>
+#endif
+/* Override any gcc2 internal prototype to avoid an error.  */
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+/* We use char because int might match the return type of a gcc2
+   builtin and then its argument prototype would still apply.  */
+char $1 ();
+/* The GNU C library defines this for functions which it implements
+    to always fail with ENOSYS.  Some functions are actually named
+    something starting with __ and the normal name is an alias.  */
+#if defined (__stub_$1) || defined (__stub___$1)
+choke me
+#else
+char (*f) () = $1;
+#endif
+#ifdef __cplusplus
+}
+#endif
+], [return f != $1;])])
+
+