Remove patches from `Cargo.toml`

[tsoutsman]

Our eventual goal is to have std depend on libtheseus. This means getting rid of the patch tables in Cargo.toml, as they only work within a workspace:

• [x] spin

  ### Patch `spin` to use the `pause` asm instruction in busy-wait loops,
  ### because the `core::hint::spin_loop()` only uses it if "sse2" is enabled.
  spin = { git = "https://github.com/theseus-os/spin-rs" }
  

• [ ] volatile

  ### use our own version of volatile which supports zerocopy
  volatile = { git = "https://github.com/theseus-os/volatile" }
  

• [ ] getopts

  ### use our own no_std-compatilbe getopts
  getopts = { git = "https://github.com/theseus-os/getopts" }
  

• [ ] smoltcp - we can probably just depend on v0.5.0

  ### use the latest version of smoltcp from github; the one on crates.io is out of date
  smoltcp = { git = "https://github.com/m-labs/smoltcp", rev = "0fedb1db9aa26712830822dd61f065deaa34d611" }
  

• [ ] libc - either upstream or remove entirely

  ### Patch `libc` so we can use libc-specific types when using `cfg(target_os = "theseus")`.
  libc = { path = "ports/libc" }
  

• [ ] core2

  ### Patch `core2` with newer functions from `std::io`, e.g., additional `Seek` trait functions
  core2 = { path = "libs/core2" }
  

• [ ] bincode - This will eventually be fixed upstream

  ### Patch `bincode` because the version on crates.io doesn't handle no_std features correctly.
  bincode = { git = "https://github.com/bincode-org/bincode" }
  

Wasmtime-related crates

• [ ] wasmparser
• [ ] backtrace
• [ ] region
• [ ] thiserror_core2

[kevinaboos]

• spin: we can probably just use the upstream directly; that needs some testing though to ensure system perf isn't affected.

• volatile: our fork of volatile has diverged significantly from the original crate; we should simply rename that and publish it as a completely different crate, with zerocopy being an optional feature/dependency.

• getopts: not upstreamable because this project is a rustc dependency. Similar to volatile we could republish it as a new package.

• smoltcp: agreed, update to v0.5.0 and/or the latest version on crates.io. An update is needed anyway to bring more key networking features to Theseus in order to support std::net components.

• libc: can eventually upstream but it's going to be a long road. Ideally we can just skip all dependencies on libc for every Theseus project.

  • I actually already changed this patch to depend on our fork via github rather than a local path to a git submodule, so that should make it easier on you in std.

• core2: i can submit a PR for our changes but it's unlikely to be accepted from what I can tell.

• bincode: yes, let's wait til v2.0 is published to crates.io

[kevinaboos]

spin patch was removed in #719