ncurses 6.2 - patch 20210821

ncurses 6.2 - patch 20210821

+ improve tparm implementation of %P and %g, more closely matching
  SVr4 terminfo.
+ move internals of TERMINAL structure to new header term.priv.h
+ add "check" rule for ncurses/Makefile
+ corrected tsl capability for terminator -TD
+ add check in tic to report instances where tparm would detect an
  error in an expression (cf: 20201010).
+ correct a few places where SP->_pair_limit was used rather than
  SP->_pair_alloc (cf: 20170812).
+ fix missing "%d" for setaf/setab code 8-15 in xterm+direct16 (report
  by Florian Weimer) -TD
+ fix some documentation errata from OpenBSD changes.
+ update config.sub