ncurses 5.6 - patch 20080823

+ modify configure check for pthread library to work with OSF/1 5.1,
  which uses #define's to associate its header and library.
+ use pthread_mutexattr_init() for initializing pthread_mutexattr_t,
  makes threaded code work on HPUX 11.23
+ fix a bug in demo_menus in freeing menus (cf: 20080804).
+ modify configure script for the case where tic library is used (and
  possibly renamed) to remove its dependency upon ncurses/ncursew
  library (patch by Dr Werner Fink).
+ correct manpage for menu_fore() which gave wrong default for
  the attribute used to display a selected entry (report by Mike Gran).
+ add Eterm-256color, Eterm-88color and rxvt-88color (prompted by
  Debian #495815) -TD