ncurses 6.0 - patch 20150725

ncurses 6.0 - patch 20150725

+ updated llib-* files.
+ build-fixes for ncurses library "test_progs" rule.
+ use alternate workaround for gcc 5.x feature (adapted from patch by
  Mikhail Peselnik).
+ add status line to tmux via xterm+sl (patch by Nicholas Marriott).
+ fixes for st 0.5 from testing with tack -TD
+ review/improve several manual pages to break up wall-of-text:
  curs_add_wch.3x, curs_attr.3x, curs_bkgd.3x, curs_bkgrnd.3x,
  curs_getcchar.3x, curs_getch.3x, curs_kernel.3x, curs_mouse.3x,
  curs_outopts.3x, curs_overlay.3x, curs_pad.3x, curs_termattrs.3x
  curs_trace.3x, and curs_window.3x