Really use cross only when cross-compiling on Linux

Author: EliahKagan

.github/workflows/release.yml

@@ -75,26 +75,32 @@ jobs:
           - build: linux
             os: ubuntu-latest
             rust: stable
+            cargo: cargo
             target: x86_64-unknown-linux-musl
           - build: linux-arm
             os: ubuntu-latest
             rust: nightly
+            cargo: cross
             target: arm-unknown-linux-gnueabihf
           - build: macos
             os: macos-latest
             rust: stable
+            cargo: cargo
             target: x86_64-apple-darwin
           - build: win-msvc
             os: windows-latest
             rust: nightly
+            cargo: cargo
             target: x86_64-pc-windows-msvc
           - build: win-gnu
             os: windows-latest
             rust: nightly-x86_64-gnu
+            cargo: cargo
             target: x86_64-pc-windows-gnu
           - build: win32-msvc
             os: windows-latest
             rust: nightly
+            cargo: cargo
             target: i686-pc-windows-msvc
         # on linux we build with musl which causes trouble with open-ssl. For now, just build max-pure there
         # even though we could also build with `--features max-control,http-client-reqwest,gitoxide-core-blocking-client,gix-features/fast-sha1` for fast hashing.
@@ -116,14 +122,10 @@ jobs:
     runs-on: ${{ matrix.os }}
 
     env:
-      # For some builds, we use cross to test on 32-bit, and maybe later big-endian, systems.
-      CARGO: cargo
-      # Whether CARGO is `cargo` or `cross`, TARGET_FLAGS will be set to `--target matrix.target`.
+      CARGO: ${{ matrix.cargo }}
       TARGET_FLAGS: --target=${{ matrix.target }}
-      # Whether CARGO is `cargo` or `cross`, TARGET_DIR will include matrix.target.
       TARGET_DIR: ./target/${{ matrix.target }}
-      # Emit backtraces on panics.
-      RUST_BACKTRACE: 1
+      RUST_BACKTRACE: 1  # Emit backtraces on panics.
 
     steps:
       - name: Checkout repository
@@ -142,11 +144,9 @@ jobs:
           toolchain: ${{ matrix.rust }}
           targets: ${{ matrix.target }}
 
-      - name: Use Cross
-        if: matrix.os == 'ubuntu-latest'
-        run: |
-          cargo install cross
-          echo 'CARGO=cross' >> "$GITHUB_ENV"
+      - name: Install Cross
+        if: matrix.cargo == 'cross'
+        run: cargo install cross
 
       - name: Show command used for Cargo
         run: |