问题
Android Studio 升级到4.1后，编译项目总是失败，报错如下：
Execution failed for task ':lib_pay:stripReleaseDebugSymbols'. > NDK at /User/**/Android/sdk/ndk-bundle did not have a source.properties file
解决
NDK at ~/Library/Android/sdk/ndk-bundle did not have a source.properties file
Android Studio 按照如下路径下载 NDK：
File -> Project Structure -> SDK Location -> "Android NDK Location"
点击 "Download" Android NDK，下载完毕后，重新编译项目，即可通过。
Download" Android NDK
