v_event_get: check qp->output for NULL before passing to e_memcmp().

Other users of qp->output already include a NULL check.
Avoids a crash when cursor key support is disabled in cl/cl_term.c.
From Jeremy Mates.  OK tb@

diff --git a/usr.bin/vi/common/key.c b/usr.bin/vi/common/key.c
index e3a85e2..8b14269 100644 (file)
--- a/usr.bin/vi/common/key.c
+++ b/usr.bin/vi/common/key.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: key.c,v 1.19 2017/04/18 01:45:35 deraadt Exp $        */
+/*     $OpenBSD: key.c,v 1.20 2022/04/21 17:50:29 millert Exp $        */
 
 /*-
  * Copyright (c) 1991, 1993, 1994
@@ -650,7 +650,10 @@ not_digit: argp->e_c = CH_NOT_DIGIT;
        }
 
        /* Find out if the initial segments are identical. */
-       init_nomap = !e_memcmp(qp->output, &gp->i_event[gp->i_next], qp->ilen);
+       if (qp->output != NULL) {
+               init_nomap =
+                   !e_memcmp(qp->output, &gp->i_event[gp->i_next], qp->ilen);
+       }
 
        /* Delete the mapped characters from the queue. */
        QREM(qp->ilen);