makefile中兩重if判斷
法一：
ifeq ($(GCC_MINOR),$(filter $(GCC_MINOR),4 5))
filter X, A B will return those of A,B that are equal X.
A variation of this is
ifneq (,$(filter $(GCC_MINOR),4 5))
where a negative comparison against an empty string is used instead (filter will return en empty string if GCC_MINOR doesn't match the arguments)
法二：
You can introduce another variable. It doesnt consolidate both checks, but it at least avoids having to put the body in twice:
do_it =
ifeq ($(GCC_MINOR), 4)
do_it = yes
endif
ifeq ($(GCC_MINOR), 5)
ifdef do_it
CFLAGS += -fno-strict-overflow
原文：
http://stackoverflow.com/questions/7656425/makefile-ifeq-logical-or