Re: rfc: fix make distinfo/makesum/mirror-distfiles for conditional distfiles

[Taylor R Campbell <campbell+netbsd-tech-pkg%mumble.net@localhost>]

   Date: Fri, 6 Mar 2015 18:02:36 +0100
   From: Marc Espie <espie%nerim.net@localhost>

   DISTFILES = master_archive.tgz
   .if $(SOME_OPTION)
   DISTFILES += file1.tgz
   .elif $(SOME_OTHER_OPTION)
   DISTFILES += file2.tgz
   .else
   DISTFILES += file3.tgz
   .endif

   SUPDISTFILES = file1.tgz file2.tgz file3.tgz

If you'll excuse the predicted NIH...  Seems to me likely to be
error-prone: easy to forget to add SUPDISTFILES.  Could do something
like DISTFILES.option1=file1.tgz and DISTSETS+=option1 to avoid this.