diff --git a/Makefile.am b/Makefile.am
index 630a1b0..1d4a528 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -2,3 +2,4 @@ SUBDIRS = build misc
 
 ACLOCAL_AMFLAGS = -I m4
 
+AM_CXXFLAGS = -wall -c89