ncurses 6.0 - patch 20170812

ncurses 6.0 - patch 20170812

+ improve description of -R option in infocmp manual page (report by
  Stephane Chazelas).
+ add reset_color_pairs() function.
+ add user_caps.5 manual page to document the terminfo extensions used
  by ncurses.
+ improve build scripts, using SIGQUIT vs SIGTRAP; add other configure
  script fixes from work on xterm, lynx and tack.
+ modify install-rule for ncurses-examples to put the data files in
  /usr/share/ncurses-examples
+ improve tracemunch, by changing address-parameters of add_wch(),
  color_content() and pair_content() to dummy parameters.
+ minor optimization to _nc_change_pair, to return quickly when the
  current screen is marked for clearing.
+ in-progress changes to improve performance of test/picsmap.c for
  loading image files.
+ modify allocation for SCREEN's color-pair table to start small, grow
  on demand up to the existing limit.
+ add "RGB" extension capability for direct-color support, use this to
  improve color_content().
+ improve picsmap test-program:
  + if no palette file is needed, attempt to load one based on $TERM,
    checking first in the current directory, then by adding ".dat"
    suffix, and finally in the data-directory, e.g.,
    /usr/share/ncurses-examples
  + add "-l" option for logging
  + add "-d" option for debugging
  + add "-s" option for stepping automatically through list of images,
    with time delay.
  + use tsearch to improve time for loading color table for images.
+ update config.guess, config.sub from
	http://git.savannah.gnu.org/cgit/config.git