The RandR protocol spec has several requests in support of user-defined
modes, but the implementation was stubbed out inside the X server. Fill out
the DIX portion and start on the xf86 DDX portion. It might be necessary to
add more code to the DDX to insert the user-defined modes into the output
mode list.
(cherry picked from commit 63cc2a51ef87130c632a874672a8c9167f14314e)
Conflicts:
randr/randrstr.h
Updated code to work in master with recent security API changes.
2c93083edd