Octave/Linux: Fix build for Octave 3.8.1 on Linux.

mkoctfile was implemented since forever as a well working
bash shell script. Somebody got bored and didn't like a
well working solution, so decided to throw it away and
rewrite mkoctfile as a compiled C++ executable with
less functionality for Octave 3.8 - Yay! :(

mkoctfile thereby lost the ability of wildcard expansion
of filenames like Common/Base/*.c and now screws up.

Reimplement wildcard expansion inside our linuxmakeitoctave3.m
make script by providing our own private override implementation
of Octave's mex.m inside our build script. This mex() function
is identical to Octave's, except it uses glob() to expand
filename wildcards like *.c into a list of all glob'bed files.
Then it passes those to mkoctfile.

-> linuxmakeitoctave3.m fixed.

-> Test rebuild of mex files under Octave 3.8.1 + Linux successfull.

-> Net result: Building PTB on Octave 3.8+ under Linux works again :)
               Another 24 hours of my life lost for no good purpose,
               just because somebody was bored and decided to make
               my life exciting.