When Cross Compiling for Android with a Standalone Toolchain, this variable holds the absolute path to the root directory of the toolchain. The specified directory must contain a sysroot subdirectory.
© 2000–2016 Kitware, Inc.
© 2000–2011 Insight Software Consortium
Licensed under the BSD 3-clause License.
https://cmake.org/cmake/help/v3.7/variable/CMAKE_ANDROID_STANDALONE_TOOLCHAIN.html