[PATCH] Preprocessor: preserve whitespace in -traditional-cpp mode.

[Jordan Rose]

  Ping.

  On IRC Richard suggested that perhaps it's not worth trying to implement -traditional-cpp in Clang, since the real -traditional-cpp is character-based rather than token-based. However, I consider this more of a patch fix to satisfy our internal developers, so that they don't need a separate binary (currently a separate //GCC// binary) to process their whitespace-sensitive configuration files. The whitespace preservation in this patch is good enough for that, and hopefully we won't need to continue piling on hacks.

http://llvm-reviews.chandlerc.com/D399