Makefile中的ifeq 多条件使用 ***

MAKEFILE多分支写法：

Android中的NDK程序android.mk判断当前是哪种CPU架构：

    ifeq ($(TARGET_ARCH), arm)
        LOCAL_SRC_FILES := ...
    else ifeq ($(TARGET_ARCH), x86)
        LOCAL_SRC_FILES := ...
    else ifeq ($(TARGET_ARCH), mips)
        LOCAL_SRC_FILES := ...
    else 
        LOCAL_SRC_FILES := ...
    endif

MAKEFILE多条件“或”：

ifneq ($(CONFIG_SUPPORT_BOOTLOADER_OTA_UPGRADE)_$(CONFIG_SUPPORT_REMOVE_LDO)_$(CONFIG_SUPPORT_TUNER_FORM_BOOT),0_0_0)
source_dir_ota += $(ROOT)/ota/mid/common
source_dir_ota += $(ROOT)/ota/driver/Tuner_demod 
source_dir_ota += $(ROOT)/ota/driver/Tuner_demod/Tuner/
source_dir_ota += $(ROOT)/ota/driver/Tuner_demod/Tuner_demod_api
CONFIG_TUNERTYPE:=$(subst ",,$(CONFIG_TUNERTYPE))

MAKEFILE多条件“与”：

ifeq ($(CONFIG_SUPPORT_BOOTLOADER_OTA_UPGRADE)_$(CONFIG_SUPPORT_REMOVE_LDO)_$(CONFIG_SUPPORT_TUNER_FORM_BOOT),y_y_y)
source_dir_ota += $(ROOT)/ota/mid/common
source_dir_ota += $(ROOT)/ota/driver/Tuner_demod 
source_dir_ota += $(ROOT)/ota/driver/Tuner_demod/Tuner/
source_dir_ota += $(ROOT)/ota/driver/Tuner_demod/Tuner_demod_api
CONFIG_TUNERTYPE:=$(subst ",,$(CONFIG_TUNERTYPE))