mesa: create a buildEnv that joins mesa (without glu) and glu

Since mesa-9.x, upstream has separated mesa and glu. @peti suggested using
buildEnv to create a mesa environment that acts like old mesa, which is what
this commit does.
wxGTK: remove reference to mesa_noglu

This is no longer needed since unifying mesa(noglu) and glu in a mesa buildEnv.
mesa: append version of mesa_noglu to mesa buildEnv name.
Merge pull request #405 from cpages/mesafix

mesa: use buildEnv to join mesa(noglu) and glu