Tests/RunCMake/CTest/Site.cmake - third_party/github.com/Kitware/CMake - Git at Google

 include(CTest)
 get_property(site CACHE SITE PROPERTY VALUE)
 if(NOT "${site}" STREQUAL "${SITE}")
   message(FATAL_ERROR "SITE is not a cache entry")
 endif()
	include(CTest)
	get_property(site CACHE SITE PROPERTY VALUE)
	if(NOT "${site}" STREQUAL "${SITE}")
	message(FATAL_ERROR "SITE is not a cache entry")
	endif()