[SourceKit] Rename Concurrency-Mac.cpp to Concurrency-libdispatch.cpp

This file builds fine as long as libdispatch is available, even on
non-Darwin platforms.

Author: briancroom

tools/SourceKit/lib/Support/CMakeLists.txt

@@ -1,4 +1,5 @@
 set(SourceKitSupport_sources
+  Concurrency-libdispatch.cpp
   FuzzyStringMatcher.cpp
   Logging.cpp
   ImmutableTextBuffer.cpp
@@ -7,13 +8,6 @@ set(SourceKitSupport_sources
   UIDRegistry.cpp
 )
 
-set(SourceKitSupport_Darwin_sources
-  Concurrency-Mac.cpp)
-set(LLVM_OPTIONAL_SOURCES ${SourceKitSupport_Darwin_sources})
-if(APPLE)
-  list(APPEND SourceKitSupport_sources ${SourceKitSupport_Darwin_sources})
-endif()
-
 set(SOURCEKIT_SUPPORT_DEPEND swiftBasic clangBasic clangRewrite)
 if(SOURCEKIT_NEED_EXPLICIT_LIBDISPATCH)
   list(APPEND SOURCEKIT_SUPPORT_DEPEND dispatch)

tools/SourceKit/lib/Support/Concurrency-Mac.cpp renamed to tools/SourceKit/lib/Support/Concurrency-libdispatch.cpp

@@ -1,4 +1,4 @@
-//===--- Concurrency-Mac.cpp ----------------------------------------------===//
+//===--- Concurrency-libdispatch.cpp --------------------------------------===//
 //
 // This source file is part of the Swift.org open source project
 //