[0/4] Input file and srcpos rework (resend again)

[Jon Loeliger]

> Thought I'd throw this patch series out there again.  It never got
> merge on the previous occasions I posted it because it conflicts with
> jdl's language enhancement patches.
> 
> But the language extension stuff seems to have fallen by the wayside
> for the time being, and in any case it shouldn't be that hard to
> update the langauge stuff on top of these cleanups.

All 4 of these patches have been applied and pushed out!

jdl