Add more IPV6_* macros to sysdeps/unix/sysv/linux/bits/in.h.

Linux 4.10 adds IPV6_RECVFRAGSIZE to include/uapi/linux/in6.h, which
shows that several such IPV6_* macros are missing from glibc's
sysdeps/unix/sysv/linux/bits/in.h (while older ones are present).  I
don't know whether any of these might be deliberately omitted, but
this patch adds what appear to be the missing more recent macros to
glibc.

Tested for x86_64.

	* sysdeps/unix/sysv/linux/bits/in.h (IPV6_AUTOFLOWLABEL): New
	macro.
	(IPV6_ADDR_PREFERENCES): Likewise.
	(IPV6_MINHOPCOUNT): Likewise.
	(IPV6_ORIGDSTADDR): Likewise.
	(IPV6_RECVORIGDSTADDR): Likewise.
	(IPV6_TRANSPARENT): Likewise.
	(IPV6_UNICAST_IF): Likewise.
	(IPV6_RECVFRAGSIZE): Likewise.