diff --git a/configure.ac b/configure.ac
index 70c9e59..ec5490f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -23,6 +23,8 @@ if test "x$CFLAGS" = "x"; then
   CFLAGS="-O3 -g"
 fi
 
+AM_PROG_CC_C_O
+
 AC_PROG_CC_C89
 if test x"$ac_cv_prog_cc_c89" = x"no"; then
   AC_MSG_ERROR([c89 compiler support required])