Alright, I wrote up another patch that uses strchr to parse out the
lines of the unaccent.rules file, foregoing sscanf completely.
Hopefully this looks a bit better than using swscanf.
As for the other problems with isspace and such on OSX, it might be
worth looking at the python portability fixes. I played briefly with
the isspace and friends macros they have and they looked okay, but I
certainly can't speak for how well they'd work for the rest of the
PostgreSQL code base.
Cheers.