upcoming update for lang/rust: 1.29.2 (miscompilation bug)

Hi,

As we are in locking state for ports, I would like to tell people about
an incoming update for lang/rust. As it will take some times to finish
it, I prefer to inform you in advance.

1.29.2 come with a workaround for aliasing-related LLVM bug causing
miscompilation.

I checked on amd64 that we are affected (the test case produce wrong
results).

Issue #54462: https://github.com/rust-lang/rust/issues/54462
Fix #54639: https://github.com/rust-lang/rust/pull/54639
Release notes: https://github.com/rust-lang/rust/blob/stable/RELEASES.md

I am working to providing diff for the release. The big part will be
recompiling on aarch64 to regenerate the PLIST (it usually take about 3
days on my hardware).

In case tagging would occurs before my diff, I don't expect
addition/deletion of files. Only Makefile, distinfo and PFRAG.*-main
files should have change.

Thanks.
--
Sebastien Marie