diff --git a/configure.ac b/configure.ac
index fec3d9f..8c52afb 100644
--- a/configure.ac
+++ b/configure.ac
@@ -6,6 +6,7 @@ AX_PREFIX_CONFIG_H([rfb/rfbconfig.h])
 
 # Checks for programs.
 AC_PROG_CC
+AM_PROG_CC_C_O
 if test -z "$CC"; then
 	CCLD="\$(CC)"
 else