Runtimes: rename Core/core to Core/Core (uppercase C) so it appears...

higher in case sensitive directory listings (like GitHub).

This will ease checking for stdlib code on small screens without needing
to scroll.

Addresses rdar://164195263

Runtimes/Core/CMakeLists.txt

@@ -206,7 +206,7 @@ add_subdirectory(Demangling)
 add_subdirectory(Threading)
 add_subdirectory(runtime)
 add_subdirectory(stubs)
-add_subdirectory(core)
+add_subdirectory(Core)
 if(SwiftCore_ENABLE_COMMANDLINE_SUPPORT)
   add_subdirectory(CommandLineSupport)
 endif()

Runtimes/Resync.cmake

@@ -86,7 +86,6 @@ set(CoreLibs
   CompatibilityOverride
   stubs
   CommandLineSupport
-  core
   SwiftOnoneSupport
   RemoteInspection
   SwiftRemoteMirror
@@ -97,6 +96,10 @@ foreach(library ${CoreLibs})
   copy_library_sources(${library} "public" "Core")
 endforeach()
 
+# copying Core/core separately, so we can specify the case of the target folder
+# correctly on case sensitive file systems
+copy_library_sources("" "public/core" "Core/Core")
+
 message(STATUS "plist[${StdlibSources}/Info.plist.in] -> Core/Info.plist.in")
 copy_files("" "Core" FILES "Info.plist.in")