diff --git a/common.mk b/common.mk
index 65fc1cc..0e8c62b 100644
--- a/common.mk
+++ b/common.mk
@@ -2,7 +2,7 @@ CC := $(CROSS)gcc
 AR := $(CROSS)ar
 RANLIB := $(CROSS)ranlib
 CFLAGS ?= -O2 -g
-CFLAGS += -Wall -Wwrite-strings -W -D_FILE_OFFSET_BITS=64
+CFLAGS += -Wall -Wextra -Wwrite-strings -Wno-sign-compare -D_FILE_OFFSET_BITS=64
 
 DESTDIR ?= /usr/local
 PREFIX=/usr