Use portable_atomics

[t-moe]

When compiling musli for my no_std project using the (riscv32) esp32-c6 I get:

error[E0432]: unresolved imports `core::sync::atomic::AtomicI64`, `core::sync::atomic::AtomicU64`
  --> /home/timo/.cargo/registry/src/index.crates.io-6f17d22bba15001f/musli-0.0.92/src/impls.rs:13:39
   |
13 |     AtomicBool, AtomicI16, AtomicI32, AtomicI64, AtomicI8, AtomicIsize, AtomicU16, AtomicU32,
   |                                       ^^^^^^^^^ no `AtomicI64` in `sync::atomic`
14 |     AtomicU64, AtomicU8, AtomicUsize,
   |     ^^^^^^^^^ no `AtomicU64` in `sync::atomic`
   |
help: a similar name exists in the module
   |
13 |     AtomicBool, AtomicI16, AtomicI32, AtomicI32, AtomicI8, AtomicIsize, AtomicU16, AtomicU32,
   |                                       ~~~~~~~~~
help: a similar name exists in the module
   |
14 |     AtomicU32, AtomicU8, AtomicUsize,
   |     ~~~~~~~~~

Could we use portable-atomics instead of core::sync::atomic?

[udoprog]

Sure.

The impls should be gated over target_has_atomic (PR incoming).

Are you interested in adding impls for portable_atomic behind a feature flag? It's unlikely that project will adopt Musli now, so for now it needs to live in here.

[t-moe]

Ah yes you're right. feature-gating is enough. I don't need portable_atomics.

thank you

[udoprog]

Glad to hear it. I'll ship a new release with the fix. Please try it out!