For what it's worth, someone with the nick name "Sc0rpius" on OFTC's #debian-next channel said glxgears works with the same versions of the libgl1-mesa-dri:i386, libgl1-mesa-glx:i386, libx11-6:i386 and libxcb1:i386 packages.
However, Sc0rpius was using x64 and an AMD card. glxgears fails for me with i386 and an nVidia card. I hope that helps, Kingsley -- Time is the fire in which we all burn.
