Pixman call needed a wrapper to fix some rendering problems in Xming

[Colin Harrison]

Here are the screenshots of a remote X client xterm on a Windows desktop via
Xming

http://www.straightrunning.com/images/good.png

http://www.straightrunning.com/images/bad.png

(sorry about the capture size differences)

I'll put some trace on the arguments to pixman_fill (in my patch) and see if
they change.
There are some other replaced fbSolidFillmmx() cases I wanted to test anyway
(I haven't seen them show an error) that may need similar refreshed
arguments for pixman_fill.

I'm happy patching for the time being anyway..let's see if any one else
suffers!

Colin