MTL: upgrade to 4.0.9507.

Closes #804.
octave 3.8.1: optional GUI & JIT
Fix for odd mkoctfile dependency issues
X11/TeX fixes
EXPERIMENT: stripping out extra link dependencies in mkoctfile, to see if it fixes the pkg problems.
Removed the keyboard patch for HEAD builds; added mkoctfile patch, pstoedit/epstool dependencies
Further remove unnecessary link dependencies in mkoctfile.