No pkg-config file for xorg in Dapper?

[Dave M G]

Adam, Michael,

As Michael says, the reason I don't use Ubuntu's nvidia drivers is 
because they don't support my card, a Galaxy Geforce 7600.

I attempted to install xserver-xorg-dev, but it Synaptic returned this 
error:

E: /var/cache/apt/archives/xserver-xorg-dev_1%3a1.0.2-0ubuntu4_i386.deb: 
trying to overwrite `/usr/share/aclocal/xorg-server.m4', which is also 
in package xserver-xgl

I don't understand what this means or what to do about it.

Can anyone tell me what to do about this?

--
Dave M G