[CMake] Copy StringProcessing files into stdlib

We want to move StringProcessing sources out of the experimental string
processing repository. Use the Resync script to copy the files from the
experimental repository into position in the StringProcessing library.

Author: etcwilde

Runtimes/Resync.cmake

@@ -127,3 +127,22 @@ copy_files(public/Platform Overlay/Windows/CRT
 
 # TODO: Add source directories for the platform overlays, supplemental
 # libraries, and test support libraries.
+
+# Supplemental Libraries
+
+# Copy StringProcessing, RegexParser, RegexBuilder
+if(NOT DEFINED StringProcessing_ROOT_DIR)
+  find_path(StringProcessing_ROOT_DIR
+    "swift-experimental-string-processing/Package.swift"
+    HINTS "${CMAKE_CURRENT_LIST_DIR}/../../")
+endif()
+message(STATUS "String Processing Root: ${StringProcessing_ROOT_DIR}")
+
+copy_library_sources(_RegexParser "Sources" "Supplemental/StringProcessing"
+  ROOT "${StringProcessing_ROOT_DIR}/swift-experimental-string-processing")
+copy_library_sources(_StringProcessing "Sources" "Supplemental/StringProcessing"
+  ROOT "${StringProcessing_ROOT_DIR}/swift-experimental-string-processing")
+copy_library_sources(_CUnicode "Sources" "Supplemental/StringProcessing/_StringProcessing"
+  ROOT "${StringProcessing_ROOT_DIR}/swift-experimental-string-processing")
+copy_library_sources(RegexBuilder "Sources" "Supplemental/StringProcessing"
+  ROOT "${StringProcessing_ROOT_DIR}/swift-experimental-string-processing")