build-libenet-ios.sh only for Mac OS.
build-libenet-android.sh support Mac OS and Windows Cygwin.
require android-ndk-11b, Android Studio could setup android-ndk-11b automatically.
Notice:
Unity 5.3.4 only support android-ndk-10e.
Mac: http://dl.google.com/android/repository/android-ndk-r10e-darwin-x86_64.zip
Windows: https://dl.google.com/android/ndk/android-ndk-r10e-windows-x86_64.exe