[gn build] Port 19af858

Author: llvmgnsyncbot

llvm/utils/gn/secondary/clang/lib/CodeGen/BUILD.gn

@@ -93,6 +93,7 @@ static_library("CodeGen") {
     "CodeGenTypes.cpp",
     "ConstantInitBuilder.cpp",
     "CoverageMappingGen.cpp",
+    "HLSLBufferLayoutBuilder.cpp",
     "ItaniumCXXABI.cpp",
     "LinkInModulesPass.cpp",
     "MacroPPCallbacks.cpp",