Slackware :: Building Mesa-7.8.1 With Osmesa Support?

I'm using Slackware 13.1, just messing around with some stuff before I upgrade to 13.37. I really want to get a decent build of Desmume working, but the 3D engine for it requires OSMesa to be enabled. I've removed the initial Mesa package that I installed from the Slackware DVD and I'm trying to recompile mesa-7.8.1 so that OSMesa is available for the system. However, I keep running into problems.

Code:

./configure --enable-gl-osmesa

When I run those options for the configure command and compile it, Mesa builds alright and gives me a working libGL just fine. It also gives me libOSMesa. Yet, when I compile Desmume to specifically use OSMesa, its configure script says that it can't find OSMesa at all. But running ldconfig -p, the output shows libOSMesa.so in /usr/lib. The symlink is up to date too, and I've recreated it several times.

Code:

./configure --with-driver=osmesa

When I build Mesa using these configure options, I don't get libGL (well, that's expected, the manual says as much will happen). But apparently libOSMesa is installed just fine. When I went to compile Desmume, no gripes about OSMesa, but Desmume needs both libGL and OSMesa to work properly.

So my question is, how can I install Mesa so that I have OpenGL and OSMesa working together? I've been able to get one working, but not both. I don't know how to get OpenGL on Slackware without using the Mesa package, but the package isn't cooperating. I'm on Intel graphics too.