[PATCH] C++ preprocessor fixes

[David Nolden]

Overall, great work (supposing that all tests except of the one
commented-out are still working). The whitespace changes in the patch
are really annoying though.

Sorry that I didn't answer to your last mail, I'm quite busy and it
required some serious thinking, which I didn't get to. Nice that
you've mostly figured out the positioning-stuff by yourself.

The changes to the macro-expander are hard to review properly for me,
I kind of hate that code, I've just spent a lot of time in it fixing
bugs and adding smaller features, basically the same way you've done
now, but it's hard for me to tell what's "right" or "wrong". Please
make sure that you have a test for each single bug you've fixed, so
things won't be broken again in future.

About the one test you've commented out: Since the checked position is
at the start of the merged token, it should be possible to map it. Why
doesn't that work anymore?

Greetings, David