Yes, it would be nice to introduce some feature for 'cygdrive' word context and get rid of it in resulting Windows files names where 'cygdrive' appear. In order to vitalize source code stepping in debug. I checked it just changing cbDebuggerPlugin::SyncEditor routine and everything's fine now at me. Al least Win7+Cygwin1.7+gdb7.3+g++-4 succeeds.
But, looking forward to get official backward compatibility and cross-platform changes.