diff --git a/Makefile b/Makefile
index 9999a09490..411669e8bf 100644
--- a/Makefile
+++ b/Makefile
@@ -355,7 +355,7 @@ GIT-VERSION-FILE: FORCE
 
 # CFLAGS and LDFLAGS are for the users to override from the command line.
 
-CFLAGS = -g -O2 -Wall
+CFLAGS = -g -O2 -Wall -Werror
 LDFLAGS =
 ALL_CFLAGS = $(CPPFLAGS) $(CFLAGS)
 ALL_LDFLAGS = $(LDFLAGS)