最近一直用android ndk来编译一些小的工具，找makefile中确定代码编译的编译开关，当时一直没有找到，后来分析了一下一般的makefile文件中的

include $(CLEAR_VARS)

这条语句，其实是对应的android源码中的

$(BUILD_SYSTEM)/clear_vars.mk

这个makefile文件

来源是

这几个参数，就需要在你编写的makefile文件中加入

LOCAL_CFLAGS := -DLUA_USE_LINUX -DLUA_COMPAT_ALL

这个变量的定义值，这样在代码的预编译的时候就使用到这些编译开关了

当然到此对于我解决那个问题已经够了，下面是clear_vars.mk这个文件中定义的变量，以便以后参考

###########################################################

## Clear out values of all variables used by rule templates.###########################################################LOCAL_MODULE:=LOCAL_MODULE_PATH:=LOCAL_MODULE_STEM:=LOCAL_DONT_CHECK_MODULE:=LOCAL_CHECKED_MODULE:=LOCAL_BUILT_MODULE:=LOCAL_BUILT_MODULE_STEM:=OVERRIDE_BUILT_MODULE_PATH:=LOCAL_INSTALLED_MODULE:=LOCAL_UNINSTALLABLE_MODULE:=LOCAL_INTERMEDIATE_TARGETS:=LOCAL_UNSTRIPPED_PATH:=LOCAL_MODULE_CLASS:=LOCAL_MODULE_SUFFIX:=LOCAL_PACKAGE_NAME:=LOCAL_OVERRIDES_PACKAGES:=LOCAL_EXPORT_PACKAGE_RESOURCES:=LOCAL_MANIFEST_PACKAGE_NAME:=LOCAL_REQUIRED_MODULES:=LOCAL_ACP_UNAVAILABLE:=LOCAL_MODULE_TAGS:=LOCAL_SRC_FILES:=LOCAL_PREBUILT_OBJ_FILES:=LOCAL_STATIC_JAVA_LIBRARIES:=LOCAL_STATIC_LIBRARIES:=# Group static libraries with "-Wl,--start-group" and "-Wl,--end-group" when linking.LOCAL_GROUP_STATIC_LIBRARIES:=LOCAL_WHOLE_STATIC_LIBRARIES:=LOCAL_SHARED_LIBRARIES:=LOCAL_IS_HOST_MODULE:=LOCAL_CC:=LOCAL_CXX:=LOCAL_CPP_EXTENSION:=LOCAL_NO_DEFAULT_COMPILER_FLAGS:=LOCAL_NO_FDO_SUPPORT :=LOCAL_ARM_MODE:=LOCAL_YACCFLAGS:=LOCAL_ASFLAGS:=LOCAL_CFLAGS:=LOCAL_CPPFLAGS:=LOCAL_RTTI_FLAG:=LOCAL_C_INCLUDES:=LOCAL_LDFLAGS:=LOCAL_LDLIBS:=LOCAL_AAPT_FLAGS:=LOCAL_AAPT_INCLUDE_ALL_RESOURCES:=LOCAL_SYSTEM_SHARED_LIBRARIES:=noneLOCAL_PREBUILT_LIBS:=LOCAL_PREBUILT_EXECUTABLES:=LOCAL_PREBUILT_JAVA_LIBRARIES:=LOCAL_PREBUILT_STATIC_JAVA_LIBRARIES:=LOCAL_PREBUILT_STRIP_COMMENTS:=LOCAL_INTERMEDIATE_SOURCES:=LOCAL_INTERMEDIATE_SOURCE_DIR:=LOCAL_JAVACFLAGS:=LOCAL_JAVA_LIBRARIES:=LOCAL_NO_STANDARD_LIBRARIES:=LOCAL_CLASSPATH:=LOCAL_DROIDDOC_USE_STANDARD_DOCLET:=LOCAL_DROIDDOC_SOURCE_PATH:=LOCAL_DROIDDOC_TEMPLATE_DIR:=LOCAL_DROIDDOC_CUSTOM_TEMPLATE_DIR:=LOCAL_DROIDDOC_ASSET_DIR:=LOCAL_DROIDDOC_CUSTOM_ASSET_DIR:=LOCAL_DROIDDOC_OPTIONS:=LOCAL_DROIDDOC_HTML_DIR:=LOCAL_ASSET_FILES:=LOCAL_ASSET_DIR:=LOCAL_RESOURCE_DIR:=LOCAL_JAVA_RESOURCE_DIRS:=LOCAL_JAVA_RESOURCE_FILES:=LOCAL_GENERATED_SOURCES:=LOCAL_COPY_HEADERS_TO:=LOCAL_COPY_HEADERS:=LOCAL_FORCE_STATIC_EXECUTABLE:=LOCAL_ADDITIONAL_DEPENDENCIES:=LOCAL_COMPRESS_MODULE_SYMBOLS:=LOCAL_STRIP_MODULE:=LOCAL_POST_PROCESS_COMMAND:=trueLOCAL_JNI_SHARED_LIBRARIES:=LOCAL_JNI_SHARED_LIBRARIES_ABI:=LOCAL_JAR_MANIFEST:=LOCAL_INSTRUMENTATION_FOR:=LOCAL_MANIFEST_INSTRUMENTATION_FOR:=LOCAL_AIDL_INCLUDES:=LOCAL_JARJAR_RULES:=LOCAL_ADDITIONAL_JAVA_DIR:=LOCAL_ALLOW_UNDEFINED_SYMBOLS:=LOCAL_DX_FLAGS:=LOCAL_CERTIFICATE:=LOCAL_SDK_VERSION:=LOCAL_SDK_RES_VERSION:=LOCAL_NDK_VERSION:=LOCAL_NDK_STL_VARIANT:=LOCAL_NO_EMMA_INSTRUMENT:=LOCAL_NO_EMMA_COMPILE:=LOCAL_PROGUARD_ENABLED:= # '',optonly,full,custom,disabledLOCAL_PROGUARD_FLAGS:=LOCAL_PROGUARD_FLAG_FILES:=LOCAL_EMMA_COVERAGE_FILTER:=LOCAL_WARNINGS_ENABLE:=LOCAL_MANIFEST_FILE:=LOCAL_RENDERSCRIPT_INCLUDES:=LOCAL_RENDERSCRIPT_INCLUDES_OVERRIDE:=LOCAL_RENDERSCRIPT_CC:=LOCAL_RENDERSCRIPT_TARGET_API:=LOCAL_BUILD_HOST_DEX:=LOCAL_DEX_PREOPT:= # '',true,false,nostrippingLOCAL_PROTOC_OPTIMIZE_TYPE:= # lite(default),micro,fullLOCAL_PROTOC_FLAGS:=LOCAL_NO_CRT:=LOCAL_PROPRIETARY_MODULE:=