More "Mega Driver" Work Merged For Mesa

More code by Emil Velikov was merged yesterday to push along the Gallium3D Mega Drivers model.

The Gallium3D mega drivers work is just like the other Mesa mega drivers model. This refactoring of the Mesa code is to basically shove multiple drivers/components into a single .so library file. By doing this, there's potential minor performance improvements through allowing the compiler to apply link-time optimizations more broadly, and it can also reduce disk space.

With Emil's work committed hours ago, the final DRI target in the Gallium3D code-base has been converted into a single DRI mega-driver library. Prior to this was the merging of some DRI targets and a number of other changes by Emil.

These changes will be found in the Mesa 10.3 release due out later this summer.