.github/workflows/build.yaml: run xlint in a void container

.github/workflows/build.yaml

@@ -20,17 +20,33 @@ jobs:
     name: Lint templates
     runs-on: ubuntu-latest
 
-    env:
-      PATH: '/usr/libexec/chroot-git:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/sbin:/usr/local/bin:/tmp/bin'
-      XLINT: '1'
-      LICENSE_LIST: common/travis/license.lst
+    container:
+      image: 'ghcr.io/void-linux/void-buildroot-musl:20230904R2'
+      env:
+        PATH: '/usr/libexec/chroot-git:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/sbin:/usr/local/bin:/tmp/bin'
+        LICENSE_LIST: common/travis/license.lst
 
     steps:
+      - name: Prepare container
+        run: |
+          # switch to repo-ci mirror
+          mkdir -p /etc/xbps.d && cp /usr/share/xbps.d/*-repository-*.conf /etc/xbps.d/
+          sed -i 's|repo-default|repo-ci|g' /etc/xbps.d/*-repository-*.conf
+          # Sync and upgrade once, assume error comes from xbps update
+          xbps-install -Syu || xbps-install -yu xbps
+          # Upgrade again (in case there was a xbps update)
+          xbps-install -yu
+          # install tools needed for lints
+          xbps-install -y grep
       - name: Clone and checkout
         uses: classabbyamp/treeless-checkout-action@v1
+      - name: Create hostrepo and prepare masterdir
+        run: |
+         ln -s "$(pwd)" /hostrepo &&
+         common/travis/set_mirror.sh &&
+         common/travis/prepare.sh &&
+         common/travis/fetch-xtools.sh
       - run: common/travis/changed_templates.sh
-      - run: common/travis/fetch-xbps.sh
-      - run: common/travis/fetch-xtools.sh
       - run: common/travis/xlint.sh
 
   # Build changed packages.