[waffle] Remove libgbm/libGL linktime dependency

[Emil Velikov]

Hello all,

As the name suggests, the series removes the hard dependency of waffle 
of the two libraries.

Note, due to the lack of link against libGL or libEGL in the final 
waffle, currently gbm will FAIL yet that is a mesa issue, which ought 
to be resolved by the time next waffle is released. 
Alternatively we'll use a hack as suggested by Frank.

The series can be found in branch for-chad/remove-libgbm-libgl-libdeps
over at github.

Cheers,
Emil