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.
wacom driver updates required for intuos 5 wacom tablet.\
Note I had to disable some recognized "pens" by using xinput disable.
So maybe 2 drivers are active?
However tilt/preasure works nicely inside gimp, inkscape, mypaint
Merge pull request #406 from MarcWeber/submit/wacom

wacom driver updates required for intuos 5 wacom tablet.
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
libpng: minor updates to 1.6.1 and 1.5.15
gtk2 platform: minor updates

Also make glib use libelf (a few hudred kBs).
gtk3: core platform update (versions from GNOME 3.8)
Fix Wine libDRM reference
Next rc for 3.9
Fix Linux 3.9-rc modDir