feat: add succinct-zkvm os and target

[nhtyy]

Adds the succinct-zkvm target and operating system. I will amend this descprtion with a PR to add std-lib support shortly

EDIT: std-lib PR currently maintained on my fork.
https://github.com/succinctlabs/rust-fork/pull/1/files

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This PR uses existing zkvm target triple style.

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[rustbot]

r? @cjgillot

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[rustbot]

These commits modify compiler targets.
(See the Target Tier Policy.)

[nhtyy]

Amended description with the std-lib pr.

[nhtyy]

@jieyouxu tagging you here as I saw you did r?, just want to confirm the right teams to tag here.

[jieyouxu]

It is correct. I will roll a compiler lead (see https://forge.rust-lang.org/compiler/proposals-and-stabilization.html#targets).

r? compiler_leads

[jieyouxu]

Please also include a Platform Support page, see https://doc.rust-lang.org/rustc/target-tier-policy.html#adding-a-new-target.

[nhtyy]

added thanks

[rustbot]

Some changes occurred in src/doc/rustc/src/platform-support

cc @Noratrieb

[nhtyy]

Updated to fix tidy lint

[Noratrieb]

By putting a dash in the target OS, you make it look like it's vendor:succinct, os:zkvm. I would recommend calling it riscv32im-succinct_zkvm-elf or even just rustc32im-succinct-elf instead

[nhtyy]

Fixed!

[nhtyy]

@Noratrieb Seems like some the UI tests are failing, is it possible I added the target incorrectly to some list, or should I update the UI fixtures?

[nhtyy]

UI tests should be fixed now!

[nhtyy]

Bump on this :) is there discussion blocking this I should be aware of

[bors]

☔ The latest upstream changes (presumably #137836) made this pull request unmergeable. Please resolve the merge conflicts.

[apiraino]

Going to reroll review for t-compiler

r? compiler

[fmease]

#t-compiler/meetings > [weekly] 2025-04-24 @ 💬
r? wesleywiser

[Enselic]

Triage: ping @wesleywiser (in the zulip thread you said you would take a look)

[wesleywiser]

Hi @nhtyy. I'm so sorry for the very long delay here.

In #135376, the compiler team decided that we should move away from zkvm as a target OS because there isn't a single operating system this represents, rather it's a series of conceptually similar but practically different operating systems.

Other than that, I think the rest of this change looks ok so if you could update the target OS name to avoid zkvm, then we can get this merged.