diff --git a/configure.in b/configure.in
index 0bb1e9eb9..07203e137 100644
--- a/configure.in
+++ b/configure.in
@@ -781,6 +781,7 @@ AM_CONDITIONAL(BITQ, test $build_bitq = yes)
 
 AC_LANG_C
 AC_PROG_CC
+AC_PROG_CC_C99
 AM_PROG_CC_C_O
 AC_PROG_RANLIB