ci(zimaos-link): set PROTOC_INCLUDE when using system protoc

Author: socoldkiller

.github/workflows/zimaos-link.yml

@@ -77,6 +77,20 @@ jobs:
         with:
           repo-token: ${{ secrets.GITHUB_TOKEN }}
 
+      - name: Export protoc include path
+        if: steps.protoc-ready.outputs.need_setup == '0'
+        run: |
+          set -euo pipefail
+          for include_dir in /usr/include /usr/local/include; do
+            if [[ -f "${include_dir}/google/protobuf/timestamp.proto" ]]; then
+              echo "PROTOC_INCLUDE=${include_dir}" >> "$GITHUB_ENV"
+              echo "Using PROTOC_INCLUDE=${include_dir}"
+              exit 0
+            fi
+          done
+          echo "google protobuf include not found under /usr/include or /usr/local/include"
+          exit 1
+
       - name: Check Rust toolchain and target
         id: rust-ready
         env: