This backports a patch that has been accepted upstream in linuxptp:
8b61aa2c3f ("udp: Avoid including
netdb.h") to fix build errors with external glibc toolchains that
provide rpc/types.h.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

In file included from print.h:25:0,
                 from linreg.c:24:
util.h:364:32: error: unknown type name 'time_t'
 int rate_limited(int interval, time_t *last);
                                ^

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>