X crashes related to Descent3

Using the mgadh-0-0-3-branch of the cvs w/
OpenGL version 1.2 Mesa 3.3 beta, X crashes when Descent3 starts to load its OpenGL code.

Descent3 version is d3full-beta1.

From the descent logs:
* FindArg: Found [-m] at argument index (2).
* OpenGL Vendor: Precision Insight, Inc.
* OpenGL Renderer: Mesa GLX Indirect
* OpenGL Version: 1.2 Mesa 3.3 beta
* OpenGL Extensions: GL_EXT_abgr GL_EXT_blend_color GL_EXT_blend_minmax GL_EXT_blend_subtract
* OpenGL: Setting up projection matrix

* OpenGL: Version is (1) major, (2) minor.
* FindArg: Did not find [--nopackedpixels] on command line.
* FindArg: Did not find [--NoMultitexture] on command line.
* OpenGL: multitextures are NOT turned on.
* OpenGL: Packed pixels are turned on.
* OpenGL: Building packed translate table...

* OpenGL: Setting states

* Setting gamma to 1.500000

* OpenGL: initialization at 640x480 was successful.

....[snip]...
* open_file_in_directory("PlasJunk.ogf", "rb", "");
* open_file_in_directory("PlasJunk.ogf", "rb", "");
* CLOSE:Renderer init is set to 1

* Shutting down networking...

* In ResetMission()

* OSIRIS: Reseting OMMS memory

* Freeing rooms...Higest_room_index -1

* Freeing all vclips!

* Freeing all bumpmap memory.

* Freeing all lightmap memory.

* Freeing all bitmap memory.

* OSIRIS: Removing Extracted DLLs

* OSIRIS: Shutting down module manager

* OSIRIS: Reseting OMMS memory

* DDIO: ddio_InternalClose() called.
* DDIO: ddio_InternalClose() returning.
* DDIO system closed.

And I'm dropped into a console.