Index: libbacktrace/configure.ac
===================================================================
--- libbacktrace/configure.ac	(revision 192824)
+++ libbacktrace/configure.ac	(working copy)
@@ -129,8 +129,15 @@ AC_SUBST(WARN_FLAGS)
 if test -n "${with_target_subdir}"; then
   GCC_CHECK_UNWIND_GETIPINFO
 else
-  AC_CHECK_FUNC(_Unwind_GetIPInfo, [have_unwind_getipinfo=yes],
+  ac_save_CFLAGS="$CFLAGS"
+  CFLAGS="$CFLAGS -Werror-implicit-function-declaration"
+  AC_TRY_COMPILE([#include "unwind.h"], [
+                    struct _Unwind_Context *context;
+                    int ip_before_insn = 0;
+                    return _Unwind_GetIPInfo (context, &ip_before_insn);
+                  ], [have_unwind_getipinfo=yes],
 		[have_unwind_getipinfo=no])
+  CFLAGS="$ac_save_CFLAGS"
   if test "$have_unwind_getipinfo" = "yes"; then
     AC_DEFINE(HAVE_GETIPINFO, 1, [Define if _Unwind_GetIPInfo is available.])
   fi