build: wire up the early swift-syntax build to the build

This enables the early swift syntax build to get us macro support on
Windows.

Author: compnerd

utils/build-windows-toolchain.bat

@@ -229,6 +229,9 @@ cmake ^
 
   -D CMAKE_INSTALL_PREFIX="%InstallRoot%" ^
 
+  -D CMAKE_Swift_COMPILER="%BuildRoot%/toolchains/PFiles64/Swift/Toolchains/0.0.0+Asserts/usr/bin/swiftc.exe" ^
+  -D CMAKE_Swift_FLAGS="-sdk %BuildRoot%/toolchains/PFiles64/Swift/Platforms/Windows.platform/Developer/SDKs/Windows.sdk" ^
+
   -D LLVM_DEFAULT_TARGET_TRIPLE=x86_64-unknown-windows-msvc ^
 
   -D PACKAGE_VENDOR="swift.org" ^
@@ -248,9 +251,11 @@ cmake ^
   -D LLVM_EXTERNAL_CMARK_SOURCE_DIR="%SourceRoot%\cmark" ^
   -D PYTHON_HOME=%PYTHON_HOME% ^
   -D PYTHON_EXECUTABLE=%PYTHON_HOME%\python.exe ^
+  -D SWIFT_PATH_TO_EARLYSWIFTSYNTAX_BUILD_DIR="%BuildRoot%\99 ^
   -D SWIFT_PATH_TO_LIBDISPATCH_SOURCE="%SourceRoot%\swift-corelibs-libdispatch" ^
   -D SWIFT_PATH_TO_SWIFT_SYNTAX_SOURCE="%SourceRoot%\swift-syntax" ^
   -D SWIFT_PATH_TO_STRING_PROCESSING_SOURCE=%SourceRoot%\swift-experimental-string-processing ^
+  -D SWIFT_PATH_TO_SWIFT_SDK="%BuildRoot%/toolchains/PFiles64/Swift/Platforms/Windows.platform/Developer/SDKs/Windows.sdk" ^
 
   -G Ninja ^
   -S llvm-project\llvm || (exit /b)