linux android gradle 打包机器：
在 android 工程根目录下的local.properties
设置：
ndk.dir=/opt/CI/android-ndk-linux/android-ndk-r9d
sdk.dir=/opt/CI/android-sdk-linux/质量构建报错：
FAILURE: Build failed with an exception.
* What went wrong:
A problem occurred configuring project ':app'.
> No toolchains found in the NDK toolchains folder for ABI with prefix: aarch64-linux-android
* Try:
Run with --stacktrace option to get the stack trace. Run with --debug option to get more log output.linux NDK 安装目录：
包上述错误：
是ndk 在local.properties设置不对，应该设置
ndk.dir=/opt/CI/android-ndk-linux/
sdk.dir=/opt/CI/android-sdk-linux/