riscv64 buildds

[Simon McVittie <smcv@debian.org>]

Two questions about the riscv64 buildds:

1. Is riscv64 still using qemu for buildds, or is it exclusively using
   real hardware now?

I ask because several packages I'm involved with have workarounds for tests
failing with a timeout on qemu, because some operations are much slower on
qemu than real hardware. If I can disable those workarounds on riscv64, then
genuine test failures will appear sooner if the test gets stuck as a result
of a bug.

Or, failing that, I'd prefer to have a way to detect "running under non-kvm
emulation" and expand timeouts when that's true, instead of detecting
riscv64 and assuming that means it might really be a slow emulation.

2. Do (some) riscv64 buildds have a smaller /tmp than is typical for other
   architectures?

gtk4 4.6.0 in experimental is currently failing to build on rv-mullvad-02
with "error writing to /tmp/ccjWWAIL.s: No space left on device", which
suggests that it might need more /tmp. gtk4 is increasingly important for
GNOME, so we'll probably want this version in unstable soon. I don't think
it does anything unusual in /tmp, it's just a relatively large package.

Please cc me in replies, I'm not subscribed to debian-riscv.

Thanks,
    smcv