Android Studio Ninja unable find

升级了Gradle和AS后，jni工程就出了这么个日狗的东西：CMake was unable to find a build program corresponding to "Ninja".  CMAKE_MAKE_PROGRAM is not set.  You probably need to select a different build tool.

在此记录下解决过程：

mac上：

1：ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)" < /dev/null 2> /dev/null

2：brew install ninja

重新编译即可。

win：

1：下载安装https://github.com/ninja-build/ninja

2：设置环境变量即可