only on build run per host

.gitea/workflows/build.yml

@@ -39,6 +39,17 @@ jobs:
           script: |
             set -e
 
+            # --- Solaris-compatible host-level lock ---
+            LOCKDIR="/tmp/build-host.lock"
+            while ! mkdir "$LOCKDIR" 2>/dev/null; do
+                echo "Another build is running on this host. Waiting..."
+                sleep 10
+            done
+            echo "Acquired host lock, starting build..."
+
+            # Ensure lock is removed on exit
+            trap "rmdir '$LOCKDIR'" EXIT
+
             echo "=== Updating sources on Solaris ${{ matrix.osver }} ==="
             cd /usr/src/buildpkg && git pull
             cd /usr/src/dbpware-for-solaris && git pull