Expand the .cargo/config.toml comment to reference both reports of
the SIGILL-at-launch bug: issue #353 (Sandy Bridge on Linux) and
discussion #343 (2012 MacBookPro9,1 / Ivy Bridge on macOS). The
macOS Intel case was diagnosed independently by @afonsojramos, who
opened PR #354 with the same fix landed earlier in b54574a7.
Also codify the forward-looking note afonsojramos suggested in that
PR: if a future hot loop needs AVX2/BMI2, the correct pattern is
per-function #[target_feature] with runtime dispatch (what the `aes`
crate already does via cpufeatures), not a global target-cpu bump
that silently breaks older hardware. This way the rationale is in
the file the next time someone is tempted to raise the baseline.
No code change, comment-only.
cc
vicrodh
3d42214775