diff --git a/GNUmakefile b/GNUmakefile
index 6b5f241812..f1433f530e 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -7,6 +7,7 @@ ifdef CONFIG
 	include $(CONFIG)
 
 	CFLAGS = -Wall \
+		-pedantic \
 		-DFACTOR_VERSION="$(VERSION)" \
 		-DFACTOR_GIT_LABEL="$(GIT_LABEL)" \
 		$(SITE_CFLAGS)