wine sources.  This was happening because HighlightMacros was 
calling EnterMainFile multiple times on the same preprocessor
object and getting an assert due to the new #line stuff (the
file in question was bison output with #line directives).

The fix for this is to not reenter the file.  Instead, 
relex the tokens in raw mode, swizzle them a bit and repreprocess
the token stream.  An added bonus of this is that rewrite macros
will now hilight the macro definition as well as its uses.  Woo.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@64480 91177308-0d34-0410-b5e6-96231b3b80d8