Tests/RunCMake/XcodeProject/ArchsStandard.cmake - third_party/github.com/Kitware/CMake - Git at Google

 if(NOT CMAKE_OSX_ARCHITECTURES STREQUAL "$(ARCHS_STANDARD)")
   message(FATAL_ERROR "CMAKE_OSX_ARCHITECTURES is not $(ARCHS_STANDARD)")
 endif()
 enable_language(C)
	if(NOT CMAKE_OSX_ARCHITECTURES STREQUAL "$(ARCHS_STANDARD)")
	message(FATAL_ERROR "CMAKE_OSX_ARCHITECTURES is not $(ARCHS_STANDARD)")
	endif()
	enable_language(C)