Add g++ as a dependency

Author: mdboom

.github/workflows/coverage.yml

@@ -56,7 +56,7 @@ jobs:
         continue-on-error: false
         with:
           # for artifact fetching, graphics libs
-          dependencies: "jq wget libgl1 libegl1"
+          dependencies: "g++ jq wget libgl1 libegl1"
           dependent_exes: "jq wget"
 
       - name: Set environment variables