fix an uninitialized variable, patch by Michael Spencer!

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@106025 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Frontend/PrintPreprocessedOutput.cpp

@@ -394,6 +394,8 @@ static void PrintPreprocessedTokens(Preprocessor &PP, Token &Tok,
   char Buffer[256];
   Token PrevPrevTok;
   Token PrevTok;
+  PrevPrevTok.setKind(tok::unknown);
+  PrevTok.setKind(tok::unknown);
   while (1) {
 
     // If this token is at the start of a line, emit newlines if needed.