Initialize variable in order to silence GCC 4.8.5 on NetBSD

Sure looks like a false-positive too me. Reported by Jenz Guenther in PR

pick.c

@@ -297,7 +297,8 @@ const struct choice *
 selected_choice(void)
 {
 	const char	*buf;
-	size_t		 choices_count, cursor_position, i, j, length, xscroll;
+	size_t		 cursor_position, i, j, length, xscroll;
+	size_t		 choices_count = 0;
 	size_t		 selection = 0;
 	size_t		 yscroll = 0;
 	int		 dofilter = 1;