Pullup ticket #6487 - requested by he
lang/rust-bin: build fix

Revisions pulled up:
- lang/rust-bin/Makefile                                        1.24

---
  Module Name: pkgsrc
  Committed By: he
  Date: Sun Jul 11 22:25:10 UTC 2021

  Modified Files:
  pkgsrc/lang/rust-bin: Makefile

  Log Message:
  Correct the names for the NetBSD versions to use.

  This uses the faster "install.sh" script, and also omits the
  "rust-doc" subset, for a much faster installation.

  This is a temporary hack for this version, will be removed on
  the next go-around.

  Apologies for this going un-committed, only myself to blame.
  Should fix part of PR#56304.

(bsiegert)