This is to help ensure buildbot builds are correct, while still gracefully disabling features in user/developer builds. * Add WITH_STRICT_BUILD_OPTIONS to give an error when features can't be enabled due to missing libraries or other reasons. Add new macro set_and_warn_library_found used everywhere features were being automatically disabled. * Remove code from Windows and macOS for various libraries that would automatically disable features. set_and_warn_library_found could be used here also, but we are generally assuming the precompiled libraries are complete and only test for availability when libraries are just added. Differential Revision: https://developer.blender.org/D16104