[gn build] Port 427c1dc

Author: llvmgnsyncbot

llvm/utils/gn/secondary/clang/lib/ASTMatchers/Dynamic/BUILD.gn

@@ -9,6 +9,7 @@ static_library("Dynamic") {
   ]
   sources = [
     "Diagnostics.cpp",
+    "Marshallers.cpp",
     "Parser.cpp",
     "Registry.cpp",
     "VariantValue.cpp",