Some Linux targets build failed prompt '--- stderr error: unknown unstable option: `linker-features`'

[Wyvern]

Rust nightly 7/10
build on several Linux targets generate

--- stderr
  error: unknown unstable option: `linker-features

previous nightly build works well without this weird error.

[Noratrieb]

@lqd @petrochenkov

[lqd]

It’s now a stable option, -Z linker-features is now -C linker-features.

[lolbinarycat]

I'm suprised we don't have a diagnostic for referring to nightly features that have been stabilized.

[Noratrieb]

We do for #![feature]s, but not for unstable compiler flags. It might be worth having a special error that looks through -C flags when it finds a -Z flags.

[workingjubilee]

reclassing as diagnostic bug