Log Message:
1) Add 'bsdlpr' option.

2) Make bsdlpr and cups options the members of a PKG_OPTIONS_NONEMPTY_SETS.
   (Because it is an error to build xfce4-print without lpr and cups support.)

3) On SunOS and Linux make cups the suggested option, otherwise make
   bsdlpr the suggested options.

Bump PKGREVISION.