Add swiftCore library

This patch hooks up the swiftCore library build and gets it installing.
This means that we have library evolution hooked up and vector types.

Building it dynamically found that we had duplicate symbols, so fixed
the swiftDemanglingCR library.

Needed to hook up the availability macros.

The flag configuration is for macOS, so we'll need to go through and
figure out what it should look like for the other platforms too.

Runtimes/Resync.cmake

@@ -29,7 +29,9 @@ function(copy_library_sources name from_prefix to_prefix)
     "${StdlibSources}/${from_prefix}/${name}/*.gyb"
     "${StdlibSources}/${from_prefix}/${name}/*.apinotes"
     "${StdlibSources}/${from_prefix}/${name}/*.yaml"
-    "${StdlibSources}/${from_prefix}/${name}/*.inc")
+    "${StdlibSources}/${from_prefix}/${name}/*.inc"
+    "${StdlibSources}/${from_prefix}/${name}/*.modulemap"
+    "${StdlibSources}/${from_prefix}/${name}/*.json")
 
   foreach(file ${filenames})
     # Get and create the directory
@@ -52,12 +54,16 @@ endfunction()
 # Copy shared core headers
 copy_library_sources(include "" "Core")
 
+# Copy magic linker symbols
+copy_library_sources("linker-support" "" "Core")
+
 set(CoreLibs
   LLVMSupport
   SwiftShims
   runtime
   CompatibilityOverride
-  stubs)
+  stubs
+  core)
 
   # Add these as we get them building
   # core