Cleanup Auxilerary Linux tests

This PR merges the "extra" Linux tests into a single job. This reduces
the number of jobs we have to run as part of the CI. We also explictly
install libc and libgcc (to make it clear these are the only extra dev
dependancies).

I also added building/linking of the x32 target. As noted in #464, this
will not run in the current github actions runner due to an incompatible
kernel config.

Signed-off-by: Joe Richey <joerichey@google.com>

Author: josephlr

.github/workflows/tests.yml

@@ -69,22 +69,21 @@ jobs:
   linux-tests:
     name: Linux Test
     runs-on: ubuntu-22.04
-    strategy:
-      matrix:
-        target: [
-          x86_64-unknown-linux-musl,
-          i686-unknown-linux-gnu,
-          i686-unknown-linux-musl,
-        ]
     steps:
       - uses: actions/checkout@v3
       - uses: dtolnay/rust-toolchain@stable
         with:
-          targets: ${{ matrix.target }}
-      - name: Install multilib
-        run: sudo apt-get update && sudo apt-get install gcc-multilib
+          targets: x86_64-unknown-linux-musl, i686-unknown-linux-gnu, i686-unknown-linux-musl, x86_64-unknown-linux-gnux32
+      - name: Install libc and libgcc for 32-bit targets
+        run: |
+          sudo apt-get update
+          sudo apt-get install --no-install-recommends libc6-dev-i386 libc6-dev-x32 lib32gcc-11-dev libx32gcc-11-dev
       - uses: Swatinem/rust-cache@v2
-      - run: cargo test --target=${{ matrix.target }} --features=std
+      - run: cargo test --target=x86_64-unknown-linux-musl --features=std
+      - run: cargo test --target=i686-unknown-linux-gnu --features=std
+      - run: cargo test --target=i686-unknown-linux-musl --features=std
+      # TODO: Find a Linux image/runner with CONFIG_X86_X32_ABI set
+      - run: cargo test --no-run --target=x86_64-unknown-linux-gnux32 --features=std
 
   ios-tests:
     name: iOS Simulator Test