Pull in the check workflow from my Boids repo

Which is, in turn, something Jonhoo put together. See the comments in
the file for more.

I mainly want the feature combination checking that this should do.

.gitea/workflows/check.yml

@@ -0,0 +1,94 @@
+# This workflow runs whenever a PR is opened or updated, or a commit is pushed to main. It runs
+# several checks:
+# - fmt: checks that the code is formatted according to rustfmt
+# - clippy: checks that the code does not contain any clippy warnings
+# - doc: checks that the code can be documented without errors
+# - hack: check combinations of feature flags
+# - msrv: check that the msrv specified in the crate is correct
+permissions:
+  contents: read
+# This configuration allows maintainers of this repo to create a branch and pull request based on
+# the new branch. Restricting the push trigger to the main branch ensures that the PR only gets
+# built once.
+on:
+  push:
+    branches: [trunk]
+  pull_request:
+# If new code is pushed to a PR branch, then cancel in progress workflows for that PR. Ensures that
+# we don't waste CI time, and returns results quicker https://github.com/jonhoo/rust-ci-conf/pull/5
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+name: check
+jobs:
+  fmt:
+    runs-on: ubuntu-latest
+    name: stable / fmt
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: true
+      - name: Install stable
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          components: rustfmt
+      - name: cargo fmt --check
+        run: cargo fmt --check
+  doc:
+    # run docs generation on nightly rather than stable. This enables features like
+    # https://doc.rust-lang.org/beta/unstable-book/language-features/doc-cfg.html which allows an
+    # API be documented as only available in some specific platforms.
+    runs-on: ubuntu-latest
+    name: nightly / doc
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: true
+      - name: Install Dependencies
+        run: sudo apt-get update; sudo apt-get install -y --no-install-recommends libasound2-dev libudev-dev libwayland-dev
+      - name: Install nightly
+        uses: dtolnay/rust-toolchain@nightly
+      - name: cargo doc
+        run: cargo doc --no-deps --all-features
+        env:
+          RUSTDOCFLAGS: --cfg docsrs
+  hack:
+    # cargo-hack checks combinations of feature flags to ensure that features are all additive
+    # which is required for feature unification
+    runs-on: ubuntu-latest
+    name: ubuntu / stable / features
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: true
+      - name: Install Dependencies
+        run: sudo apt-get update; sudo apt-get install -y --no-install-recommends libasound2-dev libudev-dev libwayland-dev cmake
+      - name: Install stable
+        uses: dtolnay/rust-toolchain@stable
+      - name: cargo install cargo-hack
+        uses: taiki-e/install-action@cargo-hack
+      # intentionally no target specifier; see https://github.com/jonhoo/rust-ci-conf/pull/4
+      # --feature-powerset runs for every combination of features
+      - name: cargo hack
+        run: cargo hack --feature-powerset check
+  msrv:
+    # check that we can build using the minimal rust version that is specified by this crate
+    runs-on: ubuntu-latest
+    # we use a matrix here just because env can't be used in job names
+    # https://docs.github.com/en/actions/learn-github-actions/contexts#context-availability
+    strategy:
+      matrix:
+        msrv: ["1.88.0"]
+    name: ubuntu / ${{ matrix.msrv }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: true
+      - name: Install Dependencies
+        run: sudo apt-get update; sudo apt-get install -y --no-install-recommends libasound2-dev libudev-dev libwayland-dev
+      - name: Install ${{ matrix.msrv }}
+        uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: ${{ matrix.msrv }}
+      - name: cargo +${{ matrix.msrv }} check
+        run: cargo check