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

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@138580 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/FrontendActions.cpp b/lib/Frontend/FrontendActions.cpp
index 4eb9cda..d6df141 100644
--- a/lib/Frontend/FrontendActions.cpp
+++ b/lib/Frontend/FrontendActions.cpp
@@ -220,7 +220,7 @@
   llvm::MemoryBuffer *Buffer
       = CI.getFileManager().getBufferForFile(getCurrentFile());
   if (Buffer) {
-    unsigned Preamble = Lexer::ComputePreamble(Buffer).first;
+    unsigned Preamble = Lexer::ComputePreamble(Buffer, CI.getLangOpts()).first;
     llvm::outs().write(Buffer->getBufferStart(), Preamble);
     delete Buffer;
   }