Add aarch64 builds to release workflow (#64)

.github/workflows/release.yml

@@ -34,6 +34,11 @@ jobs:
             target: x86_64-unknown-linux-gnu
             label: linux-x86_64
 
+          - host: linux
+            os: ubuntu-22.04
+            target: aarch64-unknown-linux-gnu
+            label: linux-aarch64
+
           - host: windows
             os: windows-latest
             target: x86_64-pc-windows-msvc
@@ -71,6 +76,14 @@ jobs:
           override: true
           profile: minimal
 
+      # No GHA runner for arm so need to cross-compile on x86
+      - name: Install arm build prerequisites
+        if: ${{ matrix.target == 'aarch64-unknown-linux-gnu' }}
+        run: |
+          sudo apt-get -y update
+          sudo apt-get -y install gcc-aarch64-linux-gnu
+          echo 'RUSTFLAGS=-C linker=aarch64-linux-gnu-gcc' >> "$GITHUB_ENV"
+
       - name: Build Release
         run: cargo build --release --locked --verbose --target ${{ matrix.target }}
         env:
@@ -82,6 +95,9 @@ jobs:
           # make binaries more portable.
           OPENSSL_STATIC: 1
 
+          # When building for arm, provide the linker for aarch64.
+          RUSTFLAGS: ${{ env.RUSTFLAGS }}
+
       - name: Create Release Archive
         shell: bash
         run: |