Thanks for adding LICENSE-related checks to pkgsrc.  I have a few more
suggestions:

1) If LICENSE= is set, warn if licenses/${LICENSE} is not present.

2) Warn if ${LICENSE} is a deprecated string.  An initial list is:

  no-commercial-use
  fee-based-commercial-use
  shareware
  no-redistribution
  no-profit

We currently have (by lame grepping):
   1 LICENSE=no-redistribution
   5 LICENSE=fee-based-commercial-use
  10 LICENSE=no-profit
  45 LICENSE=no-commercial-use

-- 
        Greg Troxel <gdt@ir.bbn.com>