merge xorg-serer 21.1.3.

merge xorg-server 1.20.3.

first merge of netbsd changes. not tested yet.

Apply patch https://bugs.freedesktop.org/attachment.cgi?id=68718
(with whitespace tweaks) from
https://bugs.freedesktop.org/show_bug.cgi?id=47266
to address graphics corruption using recent Cairo, manifested most
commonly by certain rendered text sections appearing as solid rectangular
blocks of colour.
Should be pulled up to netbsd-6 (and probably -5)

import xorg-server 1.9.2. important changes since 1.6.5 include:

- built-in symbol visibility, default not export
- fixes for various crashes
- many fixes for XI2, EXA, dix, render, glx, xkb, EDID, randr, Xv,
resource handling, Xext, vfb, xfree86 / vga and composite support.
- fixes several memory leaks
- many many documentation updates
- record extension enabled
- no longer looks for XF86Config files

initial import of xorg-server-1.6.2

initial import of xorg-server-1.6.1.901

initial import of xorg-server-1.4.2