In getttyent(3), if /etc/ttys doesn't end in a newline, don't

freak out and keep trying to expand the buffer until realloc()
fails.

PR:	114398

lib/libc/gen/getttyent.c

@@ -97,7 +97,7 @@ getttyent()
 			return (NULL);
 		}
 		/* extend buffer if line was too big, and retry */
-		while (!index(p, '\n')) {
+		while (!index(p, '\n') && !feof(tf)) {
 			i = strlen(p);
 			lbsize += MALLOCCHUNK;
 			if ((p = realloc(line, lbsize)) == NULL) {