Start running Clippy on CI

This commit configures our CI to run `cargo clippy --workspace` for all
merged PRs. Historically this hasn't been all the feasible due to the
amount of configuration required to control the number of warnings on
CI, but with Cargo's new `[lint]` table it's possible to have a
one-liner to silence all lints from Clippy by default. This commit by
default sets the `all` lint in Clippy to `allow` to by-default disable
warnings from Clippy. The goal of this PR is to enable selective access
to Clippy lints for Wasmtime on CI.

.github/workflows/main.yml

@@ -316,6 +316,10 @@ jobs:
  - run: cargo install --root ${{ runner.tool_cache }}/cargo-ndk --version ${{ env.CARGO_NDK_VERSION }} cargo-ndk
  - run: cargo ndk -t arm64-v8a check -p wasmtime
 
+ # Run clippy configuration
+ - run: rustup component add clippy
+ - run: cargo clippy --workspace
+
  # common logic to cancel the entire run if this job fails
  - run: gh run cancel ${{ github.run_id }}
  if: failure() && github.event_name != 'pull_request'

Cargo.toml

@@ -140,6 +140,9 @@ trivial_numeric_casts = 'warn'
 unstable_features = 'warn'
 unused_import_braces = 'warn'
 
+[workspace.lints.clippy]
+all = 'allow'
+
 [workspace.dependencies]
 arbitrary = { version = "1.3.1" }
 wasmtime-wmemcheck = { path = "crates/wmemcheck", version = "=16.0.0" }

crates/c-api/macros/src/lib.rs

@@ -3,8 +3,6 @@
 //! These are intended to mirror the macros in the `wasm.h` header file and
 //! largely facilitate the `declare_ref` macro.
 
-extern crate proc_macro;
-
 use proc_macro2::{Ident, TokenStream, TokenTree};
 use quote::quote;