+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
+