missing prototyped problem (bug#5521).


sql/mysqld.cc:
  Some systems (Unixware, SCO) have no prototypes for 'seteuid()' and
  'setegid()', but have them for 'setreuid()' / 'setregid()'.
  So 'sete_id(__)' calls are replaced by 'setre_id(-1,__)' (bug#5521).