Another try with caching.

.github/workflows/ci.yml

@@ -124,7 +124,10 @@ jobs:
           # We don't have a restore-keys that doesn't include the CFLAGS becouse
           # the scripts fail to run if they get different CFLAGS, and GHA offers no
           # way to manually clear the cache.
-          key: ${{ runner.os }}-configcache-${{ matrix.python-version }}-${{ env.CFLAGS }}
+          # At one time, we had a restore-key configured, and it still seems to be used
+          # even without that setting here. The whole thing is being matched even without
+          # the CFLAGS matching. Perhaps the - is a generic search separator?
+          key: ${{ runner.os }}-configcache2-${{ matrix.python-version }}-${{ env.CFLAGS }}
 
 
       - name: Install gevent