[PATCH] Don't break string literals inside preprocessor directives.

[Daniel Jasper]

  I completely agree with your FIXME :-). I think in general, we want to split strings in preprocessor definitions (at least in #defines) just the same. I think this patch as is would be a regression, as it fixes a really rare use-case at the cost of a more common one. I see two options:
  - There is already an exception for #include statements. Use the same mechanism specifically for line directives.
  - Exempt preprocessor statements starting with #define (as these seem to be the only ones where it really makes sense. If you do that, you might be able to get rid of some of the logic that currently prevents #includes from being split.

http://llvm-reviews.chandlerc.com/D1813