SDL_WinRTRunApp() is used on WinRT to launch a main(int, char **)-style
function. It has optional, and experimental support for launching content
inside a XAML control, backed by a main() function running on a separate thread.
This is provided via it's 2nd parameter, which can be a pointer to a XAML
control. (If NULL, XAML support will not be used.)
This change renames the experimental feature's parameter (to SDL_WinRTRunApp())
as "reserved", until such time as the functionality is ready for use. It will
likely be renamed again in the future, when running SDL on top of a XAML control
via a separate thread, becomes reasonably usable.
WinRT apps can set a default, preferred orientation via a .appxmanifest file.
SDL was overriding this on app startup, and making the app use all possible
orientations (landscape and portrait).
Thanks to Eric Wing for the heads up on this!
David Ludwig