RIOT-OS
rust: Update cstr dependency
Contribution description
A change in Rust nightly features broke version 0.2.5 of the cstr
crate, whose nightly-only features are enabled in some examples. The
breakage was quickly fixed upstream in the 0.2.6 version, this updates
the locks.
We could (and should, to minimize this on the long run) also stop using the nightly features -- but given that riot-wrappers are about to switch over to what the standard library now provides anyway, this is the least intrusive fix.
The issue doesn't hit us now because our Rust nightly version is pinned, but it'd hit us as soon as we updated the Rust nightly version in riotdocker.
Testing procedure
- Green CI
- The breakage before this PR only shows when using a local Rust installation and building the rust-gcoap example with a recent nightly. (I tested that).
Issues/PRs references
Builds on #18388 (they wouldn't merge conflict if I wrote them separately, but it'd still be practically useless rebasing). Look at the second change if that is
Backporting
This only needs backporting if riotdocker updates its nightly version, and after that a point release is to be made. (Because only the automated tests use the latest riotdocker image; regular users would get the riotdocker image that was versioned together with the release AIU).
Requeued in Murdock queue to give 2022.07 release backport https://github.com/RIOT-OS/RIOT/pull/18354 precedence.
