[Build] Use private_link_libraries for swiftThreading in Concurrency.

Using incorporate_object_libraries breaks the Linux build, apparently.

rdar://90776105

Author: al45tair

stdlib/public/Concurrency/CMakeLists.txt

@@ -29,10 +29,8 @@ set(swift_concurrency_private_link_libraries)
 if(CMAKE_SYSTEM_NAME STREQUAL Windows)
   list(APPEND swift_concurrency_private_link_libraries Synchronization)
 endif()
-
-set(swift_concurrency_incorporate_object_libraries)
 if(NOT SWIFT_BUILD_STATIC_STDLIB)
-  list(APPEND swift_concurrency_incorporate_object_libraries swiftThreading)
+  list(APPEND swift_concurrency_private_link_libraries swiftThreading)
 endif()
 
 if("${SWIFT_CONCURRENCY_GLOBAL_EXECUTOR}" STREQUAL "dispatch")
@@ -142,7 +140,6 @@ add_swift_target_library(swift_Concurrency ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} I
   SWIFT_MODULE_DEPENDS_WINDOWS CRT
 
   PRIVATE_LINK_LIBRARIES ${swift_concurrency_private_link_libraries}
-  INCORPORATE_OBJECT_LIBRARIES ${swift_concurrency_incorporate_object_libraries}
   LINK_LIBRARIES ${swift_concurrency_link_libraries}
 
   C_COMPILE_FLAGS