ncurses 6.2 - patch 20210522

ncurses 6.2 - patch 20210522

+ regenerate configure scripts with autoconf 2.52.20210509 to eliminate
  an unnecessary warning in config.log (report by Miroslav Lichvar).
+ add a note in manual page to explain ungetch vs unget_wch (prompted
  by discussion with Peter Farley).
+ add sp-funcs for erasewchar, killwchar.
+ modify wgetnstr, wgetn_wstr to improve compatibility with SVr4 curses
  in its treatment of interrupt and quit characters (prompted by
  report/testcase by Bill Gray)
+ update config.guess, config.sub