ncurses 6.2 - patch 20201031

ncurses 6.2 - patch 20201031

+ modify MKterm.h.in so that it is not necessary to include <curses.h>
  before <term.h> (prompted by discussion with Reuben Thomas).
+ review/improve synopsis for curs_sp_funcs.3x (prompted by discussion
  with Reuben Thomas).
+ improve format of output in tic's check_infotocap() function, to
  ensure that the messages contain only printable text.
+ modify configure-check for clang to verify that -Qunused-arguments
  is supported.  IBM's xlclang does not support it (report by Steven
  Pitman).
  needed in to tic's use-resolution when pad_char is cancelled