some general questions concerning cross-compiling pkg for armv7 and armv6

[void <void%f-m.fm@localhost>]

Hi,

I'm new to netbsd but old to freebsd so am exploring the
netbsd way of doing things. 

I was wondering if the following was possible or feasible:

1. netbsd on amd64 building packages for arm6/7 [a]
2. if some packages like rust cannot be built using the method above
3. if it is 'better' to build on arm7 for arm6 instead of amd64 for arm7/6

How frequently are packages built for arm7 and arm6 on the public builders?

These arm machines are used mainly to facilitate console access to other boxes
which are not usually equipped with an iLo or equivalent. The v7 machines
run split horizon unbound instances. So they at most need maybe 30 primary
packages that need regular building. The armv6 machine needs a lot less,
just tmux, fping, a few others. 

I'm wondering if a custom pbulk is a better way of organising this
on one machine that the others can access for updates

The destination machines are all rpis (rpi1b+, 2b+ v1.2). Machines available
for pbulk are amd64 and armv7. I'd like to avoid armv6 for compiling if I can
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