psychlasterror - Replacement for Matlab-7 'lasterror'.
This is hopefully useful for older Matlab installations and
for the Octave port:
If the 'lasterror' variable, M-File or builtin function
is supported on your Matlab installation, this function
will return it.
Otherwise, this function will return the older lasterr
variable instead.
Psychtoolbox/PsychBasic/psychlasterror.m