With 10.4.3 gpu compositing on chromium would result in a black window
on older Intel parts (ie x60s with 945gm) and at least some discrete
Radeon parts. These problems do not seem to occur on recent Intel
parts, though those have coherent memory and hardware contexts.
It isn't clear what changes in Mesa are involved in the problem
though it also occurs with the 10.3 branch.
build the Gallium3D software rasterizer as part of the libGL.
Note that it can also makes use of LLVM to build the llvmpipe if the
corresponding port is installed. Please refer to the README for a more
complete documentation.
Prodded by ajacoutot@, ok matthieu@
