Add targets that were missing in rustc

[Sycration]

The 1.51 release notes said that i386 and i486 linux were supported, but it was not included in rustc. This adds those.

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[jonas-schievink]

You'll have to add these to https://github.com/rust-lang/rust/blob/master/src/doc/rustc/src/platform-support.md as Tier 3 targets, so that CI will pass

[crlf0710]

r? @Mark-Simulacrum

[Mark-Simulacrum]

Hm, so before we merge this I would like to see the tier 3 policy requirements explicitly documented (e.g., in a comment here and a list of the maintainers).

You can see a sample of how this might be done in rust-lang/compiler-team#428 (comment), though note that MCP is seeking a slightly higher bar (Tier 2). That particular comment just addresses tier 3 status, though.

[Sycration]

Hm, so before we merge this I would like to see the tier 3 policy requirements explicitly documented (e.g., in a comment here and a list of the maintainers).

You can see a sample of how this might be done in rust-lang/compiler-team#428 (comment), though note that MCP is seeking a slightly higher bar (Tier 2). That particular comment just addresses tier 3 status, though.

Would this be acceptable? I'm still a newbie at this.

[Mark-Simulacrum]

r? @joshtriplett -- I seem to recall you having some familiarity with the relevant distinctions between i{3,4,5,6}86 targets and maybe can be a better judge of the appropriate decision here based on the writeup. My not well informed feeling is that we may want separate (or at least declared) maintainers for these targets, seeing as I believe they bring somewhat more "interesting" requirements compared to the 5/6 targets which seem to already have.

[joshtriplett]

Yeah, these targets absolutely need separate maintainers listed. Just because someone maintains i686 targets does not mean it's safe to assume they want to maintain these much older, less widely used targets.

(For that matter, we should probably determine who the maintainers of the i586 targets are, which is likely separate from the maintainers of i686.)

[joshtriplett]

Moving this to "waiting-on-author", as it needs maintainers in order to move forward.

[JohnCSimon]

Added S-blocked because it's waiting on maintainers.
cc @Sycration @joshtriplett

[JohnCSimon]

@Sycration
Ping from triage: I'm closing this due to inactivity, Please reopen when you are ready to continue with this.
Note: if you do please open the PR BEFORE you push to it, else you won't be able to reopen - this is a quirk of github.
Thanks for your contribution.

@rustbot label: +S-inactive