diff --git a/configure.ac b/configure.ac
index 92e497d..6f1cd62 100644
--- a/configure.ac
+++ b/configure.ac
@@ -38,8 +38,7 @@ AC_PATH_TOOL(AR, ar)
 AC_PATH_TOOL(RANLIB, ranlib)
 AC_PATH_TOOL(STRIP, strip)
 
-AM_PROG_CC_C_O
-AC_PROG_CC_C89
+AC_PROG_CC
 if test x"$ac_cv_prog_cc_c89" = x"no"; then
   AC_MSG_ERROR([c89 compiler support required])
 fi