netinet/in.h: add missing IP protocol numbers from the linux uapi headers
net/if_arp.h: add missing ARP hardware identifiers from linux uapi headers

the removed ARPHRD_IEEE802154_PHY was only present in the kernel api
in v2.6.31 (by accident), but it got into the glibc headers (in 2009)
and remained there since this header was not updated since then.
ptrace.h: add new ptrace requests to get/set sigmask

PTRACE_GETSIGMASK and PTRACE_SETSIGMASK were added in linux v3.11
and used by checkpoint/restore tools
sys/socket.h: add new SO_BUSY_POLL socket option

low latency busy poll sockets are new in linux v3.11