--- a/libtwin/twin_feature.c
+++ b/libtwin/twin_feature.c
@@ -55,7 +55,7 @@
 }
 
 #else
-#define _twin_have_altivec()
+#define _twin_have_altivec() 0
 #endif /* HAVE_ALTIVEC */
 
 int twin_has_feature(unsigned int feature)