pcc support

[justincormack]

I added enough pcc support to parse its output and deal with the other errors (at least in tested cases, it does not seem to be very consistent).

Missing is the following (I think thats all now...)

1. It will not compile from stdin so doesitbuild would have to save a temporary file which is annoying.
2. If you fix 1. it is still looking for gcc not pcc even though HAVE_PCC is set, for unclear reasons.

It is certainly worth someone fixing 2 (which should be fairly simple), but my main use case (fast test builds on Linux) turns out to be a non starter as pcc will not currently compile anything on Debian so not sure I am going to spend any more time on it right now.

[anttikantee]

See also #23 (maybe close that if it's fixed?)