cf. http://sourceforge.net/mailarchive/forum.php?thread_name=20120518071314.GA28061%40perso.beuc.net&forum_name=freeglut-developer */
FGAPI void FGAPIENTRY glutMultiEntryFunc( void (* callback)( int, int ) );
FGAPI void FGAPIENTRY glutMultiButtonFunc( void (* callback)( int, int, int, int, int ) );
cf. http://sourceforge.net/mailarchive/forum.php?thread_name=20120518071314.GA28061%40perso.beuc.net&forum_name=freeglut-developer */
FGAPI void FGAPIENTRY glutMultiEntryFunc( void (* callback)( int, int ) );
FGAPI void FGAPIENTRY glutMultiButtonFunc( void (* callback)( int, int, int, int, int ) );