diff --git a/Runtimes/Resync.cmake b/Runtimes/Resync.cmake
index d9f474005986f..ce5fb5f1709b3 100644
--- a/Runtimes/Resync.cmake
+++ b/Runtimes/Resync.cmake
@@ -8,49 +8,67 @@ cmake_minimum_required(VERSION 3.21)
 # Where the standard library lives today
 set(StdlibSources "${CMAKE_CURRENT_LIST_DIR}/../stdlib")
 
-message(STATUS "Source dir: ${StdlibSources}")
-
-# Copy the files under the "name" directory in the standard library into the new
-# location under Runtimes
-function(copy_library_sources name from_prefix to_prefix)
-  message(STATUS "${name}[${StdlibSources}/${from_prefix}/${name}] -> ${to_prefix}/${name} ")
+# Copy a list of files
+function(copy_files from_prefix to_prefix)
+  cmake_parse_arguments(ARG "" "ROOT" "FILES" ${ARGN})
+  if(NOT ARG_ROOT)
+    set(ARG_ROOT ${StdlibSources})
+  endif()
 
   set(full_to_prefix "${CMAKE_CURRENT_LIST_DIR}/${to_prefix}")
 
-  file(GLOB_RECURSE filenames
-    FOLLOW_SYMLINKS
-    LIST_DIRECTORIES FALSE
-    RELATIVE "${StdlibSources}/${from_prefix}"
-    "${StdlibSources}/${from_prefix}/${name}/*.swift"
-    "${StdlibSources}/${from_prefix}/${name}/*.h"
-    "${StdlibSources}/${from_prefix}/${name}/*.cpp"
-    "${StdlibSources}/${from_prefix}/${name}/*.c"
-    "${StdlibSources}/${from_prefix}/${name}/*.mm"
-    "${StdlibSources}/${from_prefix}/${name}/*.m"
-    "${StdlibSources}/${from_prefix}/${name}/*.def"
-    "${StdlibSources}/${from_prefix}/${name}/*.gyb"
-    "${StdlibSources}/${from_prefix}/${name}/*.apinotes"
-    "${StdlibSources}/${from_prefix}/${name}/*.yaml"
-    "${StdlibSources}/${from_prefix}/${name}/*.inc"
-    "${StdlibSources}/${from_prefix}/${name}/*.modulemap"
-    "${StdlibSources}/${from_prefix}/${name}/*.json")
-
-  foreach(file ${filenames})
+  foreach(file ${ARG_FILES})
     # Get and create the directory
     get_filename_component(dirname ${file} DIRECTORY)
     file(MAKE_DIRECTORY "${full_to_prefix}/${dirname}")
     file(COPY_FILE
-      "${StdlibSources}/${from_prefix}/${file}"         # From
+      "${ARG_ROOT}/${from_prefix}/${file}"              # From
       "${full_to_prefix}/${file}"                       # To
       RESULT _output
       ONLY_IF_DIFFERENT)
     if(_output)
       message(SEND_ERROR
-        "Copy ${from_prefix}/${file} -> ${full_to_prefix}/${file} Failed: ${_output}")
+        "Copy ${ARG_ROOT}/${from_prefix}/${file} -> ${full_to_prefix}/${file} Failed: ${_output}")
     endif()
   endforeach()
 endfunction()
 
+# Copy the files under the "name" directory in the standard library into the new
+# location under Runtimes
+function(copy_library_sources name from_prefix to_prefix)
+  cmake_parse_arguments(ARG "" "ROOT" "" ${ARGN})
+
+  if(NOT ARG_ROOT)
+    set(ARG_ROOT ${StdlibSources})
+  endif()
+
+  message(STATUS "${name}[${ARG_ROOT}/${from_prefix}/${name}] -> ${to_prefix}/${name} ")
+
+  set(full_to_prefix "${CMAKE_CURRENT_LIST_DIR}/${to_prefix}")
+
+  file(GLOB_RECURSE filenames
+    FOLLOW_SYMLINKS
+    LIST_DIRECTORIES FALSE
+    RELATIVE "${ARG_ROOT}/${from_prefix}"
+    "${ARG_ROOT}/${from_prefix}/${name}/*.swift"
+    "${ARG_ROOT}/${from_prefix}/${name}/*.h"
+    "${ARG_ROOT}/${from_prefix}/${name}/*.cpp"
+    "${ARG_ROOT}/${from_prefix}/${name}/*.c"
+    "${ARG_ROOT}/${from_prefix}/${name}/*.mm"
+    "${ARG_ROOT}/${from_prefix}/${name}/*.m"
+    "${ARG_ROOT}/${from_prefix}/${name}/*.def"
+    "${ARG_ROOT}/${from_prefix}/${name}/*.gyb"
+    "${ARG_ROOT}/${from_prefix}/${name}/*.apinotes"
+    "${ARG_ROOT}/${from_prefix}/${name}/*.yaml"
+    "${ARG_ROOT}/${from_prefix}/${name}/*.inc"
+    "${ARG_ROOT}/${from_prefix}/${name}/*.modulemap"
+    "${ARG_ROOT}/${from_prefix}/${name}/*.json")
+
+  copy_files("${from_prefix}" "${to_prefix}"
+    ROOT "${ARG_ROOT}"
+    FILES ${filenames})
+endfunction()
+
 # Directories in the existing standard library that make up the Core project
 
 # Copy shared core headers
@@ -59,63 +77,6 @@ copy_library_sources(include "" "Core")
 # Copy magic linker symbols
 copy_library_sources("linker-support" "" "Core")
 
-# Copy Plist
-message(STATUS "plist[${StdlibSources}/Info.plist.in] -> Core/Info.plist.in")
-file(COPY_FILE
-  "${StdlibSources}/Info.plist.in"                             # From
-  "${CMAKE_CURRENT_LIST_DIR}/Core/Info.plist.in"               # To
-  RESULT _output
-  ONLY_IF_DIFFERENT)
-if(_output)
-  message(SEND_ERROR
-    "Copy ${StdlibSources}/Info.plist.in] -> Core/Info.plist.in Failed: ${_output}")
-endif()
-
-# Copy Windows clang overlays
-message(STATUS "modulemap[${StdlibSources}/Windows/ucrt.modulemap] -> Overlay/Windows/clang")
-file(COPY_FILE
-  "${StdlibSources}/public/Platform/ucrt.modulemap"                 # From
-  "${CMAKE_CURRENT_LIST_DIR}/Overlay/Windows/clang/ucrt.modulemap"  # To
-  RESULT _output
-  ONLY_IF_DIFFERENT)
-if(_output)
-  message(SEND_ERROR
-    "Copy ${StdlibSources}/public/Platform/ucrt.modulemap -> Overlay/Windows/clang/ucrt.modulemap Failed: ${_output}")
-endif()
-
-message(STATUS "modulemap[${StdlibSources}/Windows/winsdk.modulemap] -> Overlay/Windows/clang")
-file(COPY_FILE
-  "${StdlibSources}/public/Platform/winsdk.modulemap"                 # From
-  "${CMAKE_CURRENT_LIST_DIR}/Overlay/Windows/clang/winsdk.modulemap"  # To
-  RESULT _output
-  ONLY_IF_DIFFERENT)
-if(_output)
-  message(SEND_ERROR
-    "Copy ${StdlibSources}/public/Platform/winsdk.modulemap -> Overlay/Windows/clang/winsdk.modulemap Failed: ${_output}")
-endif()
-
-message(STATUS "modulemap[${StdlibSources}/Windows/vcruntime.modulemap] -> Overlay/Windows/clang")
-file(COPY_FILE
-  "${StdlibSources}/public/Platform/vcruntime.modulemap"                # From
-  "${CMAKE_CURRENT_LIST_DIR}/Overlay/Windows/clang/vcruntime.modulemap" # To
-  RESULT _output
-  ONLY_IF_DIFFERENT)
-if(_output)
-  message(SEND_ERROR
-    "Copy ${StdlibSources}/public/Platform/vcruntime.modulemap -> Overlay/Windows/clang/vcruntime.modulemap Failed: ${_output}")
-endif()
-
-message(STATUS "APINotes[${StdlibSources}/Windows/vcruntime.apinotes] -> Overlay/Windows/clang")
-file(COPY_FILE
-  "${StdlibSources}/public/Platform/vcruntime.apinotes"                 # From
-  "${CMAKE_CURRENT_LIST_DIR}/Overlay/Windows/clang/vcruntime.apinotes"  # To
-  RESULT _output
-  ONLY_IF_DIFFERENT)
-if(_output)
-  message(SEND_ERROR
-    "Copy ${StdlibSources}/public/Platform/vcruntime.apinotes -> Overlay/Windows/clang/vcruntime.modulemap Failed: ${_output}")
-endif()
-
 set(CoreLibs
   LLVMSupport
   SwiftShims
@@ -128,36 +89,35 @@ set(CoreLibs
   Concurrency
   Concurrency/InternalShims)
 
-  # Add these as we get them building
-  # Demangling
-
 foreach(library ${CoreLibs})
   copy_library_sources(${library} "public" "Core")
 endforeach()
 
-message(STATUS "CRT[${StdlibSources}/public/Platform] -> ${CMAKE_CURRENT_LIST_DIR}/Overlay/Windows/CRT")
-foreach(file ucrt.swift Platform.swift POSIXError.swift TiocConstants.swift tgmath.swift.gyb)
-  file(COPY_FILE
-    "${StdlibSources}/public/Platform/${file}"
-    "${CMAKE_CURRENT_LIST_DIR}/Overlay/Windows/CRT/${file}"
-    RESULT _output
-    ONLY_IF_DIFFERENT)
-  if(_output)
-    message(SEND_ERROR
-      "Copy Platform/${file} -> ${CMAKE_CURRENT_LIST_DIR}/Overlay/Windows/CRT/${file} Failed: ${_output}")
-  endif()
-endforeach()
+message(STATUS "plist[${StdlibSources}/Info.plist.in] -> Core/Info.plist.in")
+copy_files("" "Core" FILES "Info.plist.in")
 
+# Platform Overlays
+
+# Windows Overlay
 message(STATUS "WinSDK[${StdlibSources}/public/Windows] -> ${CMAKE_CURRENT_LIST_DIR}/Overlay/Windows/WinSDK")
-file(COPY_FILE
-  "${StdlibSources}/public/Windows/WinSDK.swift"
-  "${CMAKE_CURRENT_LIST_DIR}/Overlay/Windows/WinSDK/WinSDK.swift"
-  RESULT _output
-  ONLY_IF_DIFFERENT)
-if(_output)
-  message(SEND_ERROR
-    "Copy Windows/WinSDK.swift -> ${CMAKE_CURRENT_LIST_DIR}/Overlay/Windows/WinSDK/WinSDK.swift Failed: ${_output}")
-endif()
+copy_files(public/Windows Overlay/Windows/WinSDK FILES WinSDK.swift)
+
+message(STATUS "Windows Modulemaps[${StdlibSources}/Platform] -> ${CMAKE_CURRENT_LIST_DIR}/Overlay/Windows/clang")
+copy_files(public/Platform Overlay/Windows/clang
+  FILES
+    ucrt.modulemap
+    winsdk.modulemap
+    vcruntime.modulemap
+    vcruntime.apinotes)
+
+message(STATUS "CRT[${StdlibSources}/public/Platform] -> ${CMAKE_CURRENT_LIST_DIR}/Overlay/Windows/CRT")
+copy_files(public/Platform Overlay/Windows/CRT
+  FILES
+    ucrt.swift
+    Platform.swift
+    POSIXError.swift
+    TiocConstants.swift
+    tgmath.swift.gyb)
 
 # TODO: Add source directories for the platform overlays, supplemental
 # libraries, and test support libraries.