Merge pull request #21551 from compnerd/gen-x

[5.0] Remove check for including Runtime due to CmakeConfig.h dependencies

Author: bob-wilson

include/swift/CMakeLists.txt

@@ -1,6 +1,4 @@
-if(SWIFT_BUILD_STDLIB OR SWIFT_BUILD_SDK_OVERLAY OR SWIFT_BUILD_STANDALONE_OVERLAY)
-  add_subdirectory(Runtime)
-endif()
+add_subdirectory(Runtime)
 
 if(SWIFT_BUILD_REMOTE_MIRROR)
   add_subdirectory(SwiftRemoteMirror)