"./x.py test mir-opt --bless" no longer works about rust HOT 4 CLOSED

xcrun seems to be some macOS/Apple SDK tool.

mir-opt --bless does build std for a bunch of foreign targets, but that used to work, so something must have changed, and now xcrun is required. I'm not even sure where that error comes from, Failed to find tool does not occur as a string in the Rust repository...

Cc @saethlin

from rust.

Maybe #122504 is related? xcrun appears in the discussion there, and this line here looks like it may be the one printing the error. Cc @jfgoog @NobodyXu

But this can't be a build script, right? bootstrap must be calling cc directly but then printing its errors without giving any context. Cc @rust-lang/bootstrap

from rust.

In general, the mir-opt test setup is designed to dodge any use of the cc crate, because the whole strategy of the mir-opt tests is oriented around not needing a C toolchain.

from rust.

I've posted a fix in #125369. It seems to work locally.

from rust.