ncurses 6.4 - patch 20230114

+ change RV to XR/xr, to avoid conflict with pre-existing usage in vim,
  to use RV/rv to denote DA2 and its response (discussion with Bram
  Moolenaar) -TD
+ add XF flag to xterm+focus so that termcap applications can be aware
  of terminals which may support focus in/out -TD
+ use xterm+focus in xterm-p370 and tmux -TD
+ improve configure-script macros vs compiler warnings.