CMake: Move -DANDROID in the toolchain script, to ease reuse of this file

[freeglut] / android_toolchain.cmake

# CMake toolchain file, cf. README.android
SET(CMAKE_SYSTEM_NAME Linux)  # Tell CMake we're cross-compiling
include(CMakeForceCompiler)
# Prefix detection only works with compiler id "GNU"
CMAKE_FORCE_C_COMPILER(arm-linux-androideabi-gcc GNU)
# '-DANDROID' is the Android build system convention
ADD_DEFINITIONS(-DANDROID)
SET(ANDROID TRUE)