In extremely rare cases, probably due to misconfigured drivers, one might
see this happen, and rather than terminate the process, we try to recover
by reporting an error to the app.
Fixes Bugzilla #3068.
There are platforms it isn't implemented on (and currently can't be
implemented on!), and there's currently no way for an app to know this.
This shouldn't break ABI on apps that moved to a revision between 2.0.3 and
2.0.4.
This relies on a successful SDL_Init(SDL_INIT_VIDEO) to work, since it's
silly to reproduce all the Xinerama/XRandR code in the message box parts. If
X11 is available but SDL hasn't been initialized, the message box will center
in the primary screen, which will be positioned weirdly on multi-head setups,
but this should fix the most significant common case.
Ryan C. Gordon