check conf.h on build server

.github/workflows/build.yml

@@ -19,6 +19,8 @@ jobs:
       run: sudo apt install -y libcmocka-dev
     - name: configure
       run: ./configure
+    - name: list conf.h for testing
+      run cat src/conf.h
     - name: build tests
       run: cd src && touch .accepted && make test
     - name: build