Instead of just GetClientRect(). This fixes a regression introduced by
3e9fe3e9. We also need to clip against e.g.
the screen edges instead of just the client rect.

quartz: If the MediaSeeking is not implemented all the way up the passthru chain fall back to the filtergraph's clock to find position.

gdi32: In update_system_links if the font we are trying to link has already been substituted or localized we need to check against that name also.