diff --git a/Makefile.am b/Makefile.am
index 1d4a528..5cc1266 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -2,4 +2,4 @@ SUBDIRS = build misc
 
 ACLOCAL_AMFLAGS = -I m4
 
-AM_CXXFLAGS = -wall -c89
+AM_CFLAGS = -wall -c89 -werror