Xcode 配置常用变量（SRCROOT, PROJECT_DIR, PROJECT_NAME）

https://developer.apple.com/library/mac/documentation/DeveloperTools/Reference/XcodeBuildSettingRef/1-Build_Setting_Reference/build_setting_ref.html

http://blog.csdn.net/phunxm/article/details/17044337

：环境变量宏（Build Setting Macros）引用格式：${MACRO}，同Build Phases Run Script中的语法。

PROJECT = HelloWorld

PROJECT_DIR =~/Projects/Learn Objective-C/HelloWorld

PROJECT_FILE_PATH =${PROJECT_DIR}/HelloWorld.xcodeproj

PROJECT_NAME = HelloWorld

SOURCE_ROOT =${PROJECT_DIR}

SRCROOT =${PROJECT_DIR}

SDKROOT = /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk

SDK_DIR = /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk

SDK_NAME = macosx10.9