pkgsrc-wip/Mesa

These packages are copy-pasta of graphics/Mesa* files. The goal is to have
a r600 dri driver...

To use this new Mesa package, you can either :

1) - copy wip/MesaLib/buildlink3.mk to graphics/MesaLib/buildlink3.mk
   - make install wip/MesaLib and wip/Mesa

2) - copy wip/gl/buildlink3.mk to graphics/MesaLib/buildlink3.mk
   - add include wip/dri/buildlink3.mk into x11/modular-xorg-server/Makefile
   - add include wip/glw/buildlink3.mk into packages that need it...
(my favorite method)

I chose modular packages (gl dri glw) over a MesaLib katamari, and used
the configure script.

It seems that binutils>=2.16 is needed for the x86-64 asm option.

Tested on :
 - NetBSD/amd64 current, options "dri asm" "dri" "", on a r700 radeon
	swrast_dri : ok
	r600_dri : libGL error: drmOpenOnce failed (Operation not permitted)
 - NetBSD/i386 current, options "dri asm", on an intel i915
	i915_dri : ok