networking: code shrink

function                                             old     new   delta
in_ether                                               -     124    +124
hexchar2int                                           42       -     -42
ifconfig_main                                       1237    1106    -131
ether_input                                          141       -    -141
------------------------------------------------------------------------------
(add/remove: 2/2 grow/shrink: 0/1 up/down: 124/-314)         Total: -190 bytes

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
date: accept 'yyyy-mm-dd HH' and 'yyyy-mm-dd' date formats

function                                             old     new   delta
parse_datestr                                        794     885     +91

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Add notes about TCP programming quirks.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
buildsys: Add helper to list suid applets

Add a helper script that lists all applets that
- do or may require SUID provileges (busybox.cfg.suid)
- do not require SUID provileges (busybox.cfg.nosuid)

Some setups prefer to build two busybox binaries, one that is suid which
contains all applets that do or may require suid privileges, and a
second one for all the rest (which drops suid). To ease splitting these
two binaries, generate a list of CONFIG_ items for the suid binary.

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
Update docs/tcp.txt

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>