mac 下载源码 most ports 报错误 Unable to execute port: can't read "build.cmd":

POSIXLY_CORRECT=1 sudo port install gmake libsdl git-core gnupg
Warning: The Command Line Tools for Xcode don't appear to be installed; most ports will likely fail to build.
Warning: See http://guide.macports.org/chunked/installing.xcode.html for more information.

--->  Computing dependencies for gmakeError: Unable to execute port: can't read "build.cmd": Failed to locate 'make' in path: '/opt/local/bin:/opt/local/sbin:/bin:/sbin:/usr/bin:/usr/sbin' or at its MacPorts configuration time location, did you move it?

上面有提示说 xcode 命令行工具没有安装 具体在xcode 偏好设置(Preferences..) downloads 中 Components 标签 中 有命令行工具 点击下载