[Swift 5.6 compat] use compat threading library

Author: etcwilde

stdlib/toolchain/Compatibility56/CMakeLists.txt

@@ -13,7 +13,7 @@ add_swift_target_library("${library_name}" STATIC
 
   C_COMPILE_FLAGS ${CXX_COMPILE_FLAGS}
   LINK_FLAGS ${CXX_LINK_FLAGS}
-  INCORPORATE_OBJECT_LIBRARIES swiftThreading
+  INCORPORATE_OBJECT_LIBRARIES swiftCompatibilityThreading
   SWIFT_COMPILE_FLAGS ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
   DEPLOYMENT_VERSION_OSX ${COMPATIBILITY_MINIMUM_DEPLOYMENT_VERSION_OSX}
   DEPLOYMENT_VERSION_IOS ${COMPATIBILITY_MINIMUM_DEPLOYMENT_VERSION_IOS}