-CFLAGS := -Wall -O2 -Werror -Wno-unknown-pragmas $(PYINCLUDE) $(CFLAGS)
-CFLAGS := -D_FILE_OFFSET_BITS=64 $(CFLAGS)
+CFLAGS := -O2 -Wall -Werror -Wformat=2 $(CFLAGS)
+CFLAGS := -Wno-unknown-pragmas -Wsign-compare $(CFLAGS)
+CFLAGS := -D_FILE_OFFSET_BITS=64 $(PYINCLUDE) $(CFLAGS)