在Android的编译脚本中有很多示例，比如在 build/core/main.mk 文件中：
ifeq ($(BUILD_OS),linux)
build_arch := $(shell uname -m)
ifneq (64,$(findstring 64,$(build_arch)))
$(warning ************************************************************)
$(warning You are attempting to build on a 32-bit system.)
$(warning Only 64-bit build environments are supported beyond froyo/2.2.)
$(warning ************************************************************)
$(error stop)
endif
endif
ifneq ($(HOST_OS),windows)
ifneq ($(HOST_OS)-$(HOST_ARCH),darwin-ppc)
# check for a case sensitive file system
ifneq (a,$(shell mkdir -p $(OUT_DIR) ; \
echo a > $(OUT_DIR)/casecheck.txt; \
echo B > $(OUT_DIR)/CaseCheck.txt; \
cat $(OUT_DIR)/casecheck.txt))
$(warning ************************************************************)
$(warning You are building on a case-insensitive filesystem.)
$(warning Please move your source tree to a case-sensitive filesystem.)
$(warning ************************************************************)
$(error Case-insensitive filesystems not supported)
endif
endif
endif