Comment 8 for bug 1440186

Launchpad strikes again... I forgot to subscribe to notification emails, and didn't refresh the webpage until just now. So I didn't see comments #5 and #6 before committing my patch.

While a union would save sizeof(void*) for each allocation, I don't like this practice as it will allow write-after-free bugs to corrupt the linked list, probably leading to a segfault during a future allocation.