new 'xvmc' branch of intel video driver

[R. G. Newbury]

I have been able to compile the entire xorg source tree and the 
xf86free-video-intel driver with the new xvmc branch included.


However, now I find I do not know how to test this alongside the old 
version.
Copying the new intel_drv.so into /usr/lib/xorg/modules/drivers fails. X 
will not start, reporting a 'module mismatch error'.

Munging PATH and ld.so.conf to put the /tmp/modular/bin and 
/tmp/modular/lib folders into the path ahead of the normal references 
did not work. Xorg.0.old continued to report that the module path is 
/usr/lib/xorg.

So how do I *test* the new stuff? By which I mean, I can come back to 
the present setup..
I cannot find any instructions on the xorg site or wiki.

TIA

Geoff