use flag streflop of megaglest has a typo in the description: "Use the library streflop. Out of synchs may occur if not enabled." should be "Use the library streflop. Out of syncs may occur if not enabled." see also the list here: http://www.gentoo.org/dyn/use-index.xml
IMHO, that's bogus since either way is equally wrong as they are both abbreviations. Plus, I've seen both versions in use. However, I'd like to encourage you to fix this issue by yourself (say, in a local portage override) because (a) it's fun to learn creating ebuilds, and (b) you'd be able to contribute patches for future issues you encounter. Would that work for you ?
either spelling is fine.