Update backend.yml

Author: ExquisiteCore

.github/workflows/backend.yml

@@ -87,6 +87,12 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: Install cross-compilation toolchain for ARM64
+        if: matrix.target.target == 'aarch64-unknown-linux-gnu'
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y gcc-aarch64-linux-gnu
+
       - name: Setup Rust
         uses: actions-rs/toolchain@v1
         with: