Rev the distfile patch.
  - roll in patch-xfile.hc
  - fix build with the solaris compiler
  - use snprintf instead of sprintf (mostly)
  - tidy a few things

There is a problem between this thing's precompiler and clang such
that clang builds fail with spurious errors about unterminated string
constants. I don't see what's wrong.

Also, in the course of doing the snprintf changes I discovered that
this depends on both csh and netpbm existing at runtime, so add the
necessary bits.

PKGREVISION -> 4.

(dholland)