transpile: upgrade most things for edition 2024

[kkysen]

This fixes the following differences with edition 2024:

• #[unsafe(no_mangle)]
• #[unsafe(export_name = "")]
• #[unsafe(link_section = "")]
• unsafe extern "C" {
• (transpile: make extern "C" { fns unsafe by default in edition 2024 #1663) unsafe fns and safe fns in unsafe extern "C" {}s
  • not required, default to unsafe fns
• #![feature(stdsimd)] removed and split up
• stabilized #![feature(raw_ref_op)] removed
• stabilized #![feature(label_break_value)] removed
• stabilized #![feature(asm)] removed
• [profile.release] strip = "debuginfo" being the default
• (transpile: fix atomic intrinsics in edition 2024  #1658) updated atomic intrinsics (atomics.c)
• (transpile: Dedup keywords #1636) gen reserved keyword (keywords.c)
• (transpile: fix variadics in edition 2024 #1657) updated VaListImpl (varargs.c)
• (transpile: add unsafe {} blocks in unsafe fns and add #![deny(unsafe_op_in_unsafe_fn)] #1662) #[warn(unsafe_op_in_unsafe_fn)] enabled by default
  • In tests/unit/, we add #![allow(unsafe_op_in_unsafe_fn)] for now.
  • Proper fix of an outer unsafe block in unsafe fns (or finer-grained ones) we can do later.
• (transpile: replace pref_align_of with align_of in edition 2024 #1656) pref_align_of removed (Remove rustc's notion of "preferred" alignment AKA __alignof rust-lang/rust#141803)
  • used to translate __alignof
  • no alternative, so may have to drop support

This also runs the correct rustfmt, as we were previously just picking up whichever one rustup resolved.

• Fixes #![feature(stdsimd)] was split up and removed in 1.78, so stop emitting it when we upgrade past 1.65 #1298.

This updates all of the transpiler snapshot tests and tests/unit/ tests that work on edition 2024 with the above fixes. The remaining fixes I'll fix in separate PRs, as they might be trickier.

[Rua]

In the 2024 edition, the unsafe-op-in-unsafe-fn lint now also warns by default. A simple fix could be to just add an extra unsafe { } block to each function, but ultimately marking only the actual unsafe operations as unsafe could be preferred.

[kkysen]

In the 2024 edition, the unsafe-op-in-unsafe-fn lint now also warns by default. A simple fix could be to just add an extra unsafe { } block to each function, but ultimately marking only the actual unsafe operations as unsafe could be preferred.

It's still just a warning, and we have plenty of warnings already, so I don't think I'll fix it as part of this PR, but you're right, we should fix it. We can do an outer unsafe {} block first, and if possible, narrow it.

[ahomescu]

Could be named slightly better, e.g., attr_needs_unsafe.

[kkysen]

Hmm, I feel like attr_needs_unsafe implies it'll return a bool, whereas this returns Unsafety. I'm going to merge this now as-is, but I can come back and change this later.