add_executable() with ANDROID_GUI generates an executable that's named like a shared library
set(CMAKE_ANDROID_GUI 1) add_executable(MyApp main.cpp)
libMyApp.so, which looks like a shared library, but is actually an executable, and thus requires an
int main(). However, Android expects
void android_main(android_app* state). We should update CMake to build
ANDROID_GUI targets like shared libraries instead of executables.