Fix messenger compile errors on gcc / clang.
Fix messenger compile errors on gcc / clang.

arokem/python-matlab-bridge,arokem/python-matlab-bridge,blink1073/python-matlab-bridge,blink1073/python-matlab-bridge,blink1073/python-matlab-bridge,jjangsangy/python-matlab-bridge,jjangsangy/python-matlab-bridge,arokem/python-matlab-bridge,jjangsangy/python-matlab-bridge