pull out terminfo's cub1

src/lib/internal.h

@@ -137,6 +137,7 @@ typedef struct notcurses {
   char* cup;      // move cursor
   char* cuf;      // move n cells right
   char* cuf1;     // move 1 cell right
+  char* cub1;     // move 1 cell left
   char* civis;    // hide cursor
   // These might be NULL, and we can more or less work without them. Check!
   char* clearscr; // erase screen and home cursor

src/lib/notcurses.c

@@ -528,6 +528,7 @@ interrogate_terminfo(notcurses* nc, const notcurses_options* opts){
   term_verify_seq(&nc->clearbol, "el1");
   term_verify_seq(&nc->cuf, "cuf"); // n non-destructive spaces
   term_verify_seq(&nc->cuf1, "cuf1"); // non-destructive space
+  term_verify_seq(&nc->cub1, "cub1");
   term_verify_seq(&nc->smkx, "smkx"); // set application mode
   if(nc->smkx){
     if(putp(tiparm(nc->smkx)) != OK){