The checks in the incdefs.sh script do not fully work when cross
compiling. It probably checks the hosts libc. Just provide the settings
manually, as our musl at least supports all these features.

Signed-off-by: Hauke Mehrtens <hauke.mehrtens@intel.com>

Instead of cloning the released version via git, just download it via
http from sourceforge.

Signed-off-by: Hauke Mehrtens <hauke.mehrtens@intel.com>

Signed-off-by: Wojciech Dubowik <klute99@gmail.com>

ccache_cc -Wall -DVER=1.6  -D_GNU_SOURCE -DHAVE_CLOCK_ADJTIME -DHAVE_POSIX_SPAWN -DHAVE_ONESTEP_SYNC     -c -o ptp4l.o ptp4l.c
cc1: note: someone does not honour COPTS correctly, passed 0 times

unpatched
  8229 hwstamp_ctl
128213 phc2sys
 37045 phc_ctl
 99077 pmc
185589 ptp4l
 41141 timemaster

patched (honouring -Os CFLAG)
  8213 hwstamp_ctl
 54469 phc2sys
 20645 phc_ctl
 49877 pmc
 74965 ptp4l
 20645 timemaster

Signed-off-by: Stephen Walker <stephendwalker+github@gmail.com>

Linuxptp is a user space software implementation of IEEE 1588
Precision Time Protocol standard.

Signed-off-by: Wojciech Dubowik <Wojciech.Dubowik@neratec.com>
Reviewed-by: John Crispin<blogic@openwrt.org>