cmake HAVE_OBJC examples

swiftlang/swift-corelibs-libdispatch CMakeLists.txt :230 

check_include_files("objc/objc-internal.h" HAVE_OBJC)

swiftlang/swift-corelibs-libdispatch src/swift/CMakeLists.txt :29 

target_link_libraries(swiftDispatch PRIVATE
  $<$<BOOL:${HAVE_OBJC}>:DispatchStubs>
  BlocksRuntime::BlocksRuntime)