*: use llist_pop for traverse-and-free list operation

function                                             old     new   delta
append_file_list_to_list                             109     111      +2
udhcpc_main                                         2414    2413      -1
run_parts_main                                       325     324      -1
od_main                                             2324    2323      -1
getopt_main                                          709     707      -2
env_main                                             253     251      -2
sed_main                                             659     656      -3
ps_main                                              522     519      -3
traceroute_main                                     3960    3954      -6
sort_main                                            844     838      -6
diff_main                                            866     858      -8
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/10 up/down: 2/-33)            Total: -31 bytes

diff --git a/libbb/getopt32.c b/libbb/getopt32.c
index 4b5a7d2..86c3348 100644
--- a/libbb/getopt32.c
+++ b/libbb/getopt32.c
@@ -137,7 +137,7 @@
         opt_complementary = "vv:b::b-c:c-b";
         f = getopt32(argv, "vb:c", &my_b, &verbose_level);
         if (f & 2)       // -c after -b unsets -b flag
-                while (my_b) { dosomething_with(my_b->data); my_b = my_b->link; }
+                while (my_b) dosomething_with(llist_pop(&my_b));
         if (my_b)        // but llist is stored if -b is specified
                 free_llist(my_b);
         if (verbose_level) printf("verbose level is %d\n", verbose_level);