This function applies a single mode to the screen (as from RandR 1.1,
XFree86-VidModeExtension or XFree86-DGA) using a policy that selects one
output to reconfigure to the requested mode and then makes all other outputs
fit within that size.
(cherry picked from commit 5a595c1f767a8d666348b845d18934aee0cfe38f)