This backports a patch that has been accepted upstream in linuxptp:
8b61aa2c3f3103db1d4ca1d1e49bb4f8831c1abf ("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>
