[SDL] Refresh rate?

[Mattias Engdegård]

>I notice SDL_VideoInfo has no field for refresh rate.  Although the user
>might know what refresh rate the current desktop video mode is running at,
>it would be nice to know what refresh rate(s) a particular fullscreen mode
>has available.

the refresh rate isn't always available. The usual solution is to make your
game independent of the refresh rate as far as possible and just depend on
timing (this will help for targets which cannot synch to vertical refresh)

for some uses (mainly emulators) it would be useful to request a particular
refresh rate. I wouldn't mind having that in the next development branch