Corrected the computation itself (do not move pointers, but the .start field!).
Define posix_timer_adjust_all and its alias pp_timer_adjust_all

Actually, the best way for implementing timers is to use MONOTONIC_RAW which
avoids the need of such an adjust function

PP_DEFAULT_NO_ADJUST must be set to 0, otherwise the slave would not adjust
the time. It can be set to 1 with -t parameter in cmd line: this can be useful
for debug purpose, but must not be the default.

The correct one is in rt_opts struct. Removed the oldest one, which was still
used (but not set to its default) and lead to a division by zero

This fixes a misunderstanding by my side on ptpd's code. Timers are
not single-shots, but must be fired once every 'interval', where
interval is defined in timer_start. If one wants to stop it, a
timer_stop can be called
Signed-off-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>

gPTP uses the peer multicast address for all packets
Signed-off-by: Eliot Blennerhassett <eblennerhassett@audioscience.com>

pass correct payload to state machine
check minimum packet size when receiving it

Signed-off-by: Eliot Blennerhassett <eblennerhassett@audioscience.com>

Signed-off-by: Eliot Blennerhassett <eblennerhassett@audioscience.com>

Then, both spec and bare-linux pre-set ETHERNET_MODE

This moves some constants from pptp.h to constansts.h and
adds DEFAULT_ETHERNET_MODE, so archs can activate it by default for them

Note that default management is awfully broken (we inherited from the
other ptpd). For example DEFAULT_INBOUND_LATENCY is not used, and if
you change it you have no effect.

The command line is not available in freestanding environments: move
it to lib/ so archs can pick it up (e.g. arch-gnu-linux does it)