the nature of pkgsrc support for OS versions (release vs stable)

[Greg Troxel <gdt%lexort.com@localhost>]

pkgsrc has long had a notion that we "support" the versions of NetBSD
that are under maintenance, meaning the current and previous releases.
This notion probably applies to other operating systems, but I'm going
to just talk abotu NetBSD for now. 

(I'm going to ignore netbsd-7 in this discussion; that's going away soon
and makes the ABI issue more complicated.)

Due to ABI stability rules, we have considered 8.0-RELEASE and
8.x-STABLE as more or less the same thing.  This is 99+% true.  Often we
can make pkgsrc such that packages build on all points along the release
to the current stable, for each branch, and obviously if that can be
done reasonably we should do it.

Recently, we have found bugs in ld.so that break rust builds and these
have been pulled up to the stable branches.

In theory, binaries built on a system with these fixes will work on a
RELEASE system.  No one has so far presented evidence to the contrary.

Manuel has requested that anything needed to build packages other than
"use RELEASE with defaults" be documented for bulk builders.  That's a
reasonable request and I will create a wiki page about it.

So, the big question is:

  Does pkgsrc need to support *building* on 8.0_RELEASE, even when that
  version has bugs that are fixed in 8.X_STABLE, and it's not reasonable
  to work around this?

I would say no, that while pkgsrc should ideally be buildable on
RELEASE, if the problem is a bug in RELEASE, then it's entirely
reasonable to expect people *building packages* to update to a STABLE
with the fix.

While this is a general issue in theory, it is particularly important
for rust.