rust-1.31 hanging often during compiles

[Benny Siegert <bsiegert%gmail.com@localhost>]

Something I remarked in my last pkg_rr run: lang/rust seems to hang
(with 0% cpu usage) during the compile every now and then. I had to
Ctrl+c and restart the build maybe five times. The location of the
hang is not deterministic.

This also happened in wip/tealdeer (which is in Rust and built using Cargo).

Ideas? Would you like me to attach to a running process and see where
it is stuck?

This is on NetBSD-current, freshly updated, amd64.

-- 
Benny