--- m4/as-unaligned-access.m4.orig	2009-02-27 06:40:08.000000000 +1100
+++ m4/as-unaligned-access.m4	2022-06-20 02:15:14.000000000 +1000
@@ -19,6 +19,8 @@
   fi
   if test x"$as_cv_unaligned_access" = x ; then
     AC_TRY_RUN([
+#include <string.h>
+
 int main(int argc, char **argv)
 {
   char array[] = "ABCDEFGH";
