diff --git a/configure.ac b/configure.ac
index 0030967..92ba30f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -37,6 +37,7 @@ AC_CONFIG_HEADERS([config.h])
 dnl Checks for programs.
 
 AC_PROG_CC
+AM_PROG_CC_C_O
 AC_PROG_CPP
 AC_PROG_INSTALL