Log Message:
Relax ONLY_FOR_PLATFORM and accept 9.99.*
Quotin Greg Troxel:
 I think we should just allow 9.99.  While really it's 9.99.64 and up,
 pkgsrc is only expected to work on current current, and ancient current
 is no longer of interest.

issue on 9.99.100 reported by oskar@fessel.org on port-xen@