Fix the build on win32.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@64556 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Driver/ASTConsumers.h b/Driver/ASTConsumers.h
index 0093a70..2032a2d 100644
--- a/Driver/ASTConsumers.h
+++ b/Driver/ASTConsumers.h
@@ -30,7 +30,7 @@
 class Preprocessor;
 class PreprocessorFactory;
 struct CompileOptions;
-struct LangOptions;
+class LangOptions;
 
 ASTConsumer *CreateASTPrinter(llvm::raw_ostream* OS = NULL);