attempt to limit possible const_cast damage * Array.h (Array<T>::mex_get_data): Delete. * Sparse.h (Sparse<T>::mex_get_data, Sparse<T>::mex_get_ir, Sparse<T>::mex_get_jc): Delete. * oct-inttypes.h (octave_int<T>::mex_get_data): Delete. * mex.cc (mxArray_octave_value::get_data, mxArray_octave_value::get_ir, mxArray_octave_value::get_jc): Cast away const here, not in octave_value methods. * ov.h, ov.cc (octave_value::mex_get_data, octave_value::mex_get_ir, octave_value::mex_get_jc): Return const void pointer. * ov-base.h (octave_base_value::mex_get_data, octave_base_value::mex_get_ir, octave_base_value::mex_get_jc): Likewise. Change all derived classes.