libbb: add strncpy_IFNAMSIZ

function                                             old     new   delta
...
udhcp_read_interface                                 225     220      -5
brctl_main                                          1151    1146      -5
add_interface                                        109     104      -5
ipaddr_list_or_flush                                2174    2167      -7
do_add_ioctl                                          88      80      -8
vconfig_main                                         249     240      -9
do_del_ioctl                                          78      68     -10
do_iplink                                           1186    1173     -13
do_if_fetch                                          766     753     -13
buffer_fill_and_print                                196     179     -17
parse_args                                          1709    1684     -25
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/20 up/down: 11/-140)         Total: -129 bytes

1 files changed, 1 insertions, 1 deletions

diff --git a/networking/arping.c b/networking/arping.c
index aba32b869..e4429973b 100644
--- a/networking/arping.c
+++ b/networking/arping.c
@@ -286,7 +286,7 @@ int arping_main(int argc UNUSED_PARAM, char **argv)
                 struct ifreq ifr;
 
                 memset(&ifr, 0, sizeof(ifr));
-                strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name) - 1);
+                strncpy_IFNAMSIZ(ifr.ifr_name, device);
                 /* We use ifr.ifr_name in error msg so that problem
                  * with truncated name will be visible */
                 ioctl_or_perror_and_die(sock_fd, SIOCGIFINDEX, &ifr, err_str, "not found");