Fix a stringizing bug that Neil noticed.  We should preprocess this:
#define t(x) #x
t(a
c)

to "a c", not "ac".

llvm-svn: 40060
diff --git a/clang/Lex/Preprocessor.cpp b/clang/Lex/Preprocessor.cpp
index bc7ad12..7b6c571 100644
--- a/clang/Lex/Preprocessor.cpp
+++ b/clang/Lex/Preprocessor.cpp
@@ -613,7 +613,8 @@
   // If this is a function-like macro, read the arguments.
   if (MI->isFunctionLike()) {
     // C99 6.10.3p10: If the preprocessing token immediately after the the macro
-    // name isn't a '(', this macro should not be expanded.
+    // name isn't a '(', this macro should not be expanded.  Otherwise, consume
+    // it.
     if (!isNextPPTokenLParen())
       return true;
     
@@ -731,7 +732,8 @@
 
   unsigned NumActuals = 0;
   while (Tok.getKind() == tok::comma) {
-    // C99 6.10.3p11: Keep track of the number of l_parens we have seen.
+    // C99 6.10.3p11: Keep track of the number of l_parens we have seen.  Note
+    // that we already consumed the first one.
     unsigned NumParens = 0;
     
     while (1) {