Make Lexer::ComputePreamble accept a LangOptions parameter, otherwise it may be
out-of-sync how a file is compiled. Patch by Matthias Kleine!

llvm-svn: 138580
diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index e369f43..71f9c0d 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -1122,7 +1122,9 @@
     CreatedBuffer = true;
   }
   
-  return std::make_pair(Buffer, Lexer::ComputePreamble(Buffer, MaxLines));
+  return std::make_pair(Buffer, Lexer::ComputePreamble(Buffer,
+                                                       Invocation.getLangOpts(),
+                                                       MaxLines));
 }
 
 static llvm::MemoryBuffer *CreatePaddedMainFileBuffer(llvm::MemoryBuffer *Old,