MFH: r374489

Fix multiple xserver security advisories in the 1.12.4 xserver.

The patches where not ported to 1.7.7 so mark it forbidden. This version
is not default anymore and will be removed in the 1.14 update that currently
being tested.

Obtained from:	xserver upstream
Security:	27b9b2f0-8081-11e4-b4ca-bcaec565249c
Approved by:	portmgr (bapt)