diff --git a/config/Rules.am b/config/Rules.am
index 3146da6ee1..cbef12e213 100644
--- a/config/Rules.am
+++ b/config/Rules.am
@@ -23,7 +23,7 @@ endif
 
 AM_LIBTOOLFLAGS = --silent
 
-AM_CFLAGS  = -std=gnu99 -Wall -Wstrict-prototypes -Wmissing-prototypes
+AM_CFLAGS  = -std=gnu99 -Wall -Wextra -Wstrict-prototypes -Wmissing-prototypes -Wno-sign-compare -Wno-missing-field-initializers
 AM_CFLAGS += -fno-strict-aliasing
 AM_CFLAGS += $(NO_OMIT_FRAME_POINTER)
 AM_CFLAGS += $(IMPLICIT_FALLTHROUGH)