linuxolator: add netlink support

[melifaro]

Summary

Compat part for running Linux binaries with Netlink ( D36002 ).

Test Plan

Please see testing section in D36002.

[melifaro]

Update to recent -HEAD.

[dchagin]

mostly style, thank you! tested with 2.35 glibc tests suite, inet tests completed!

sys/compat/linux/linux_netlink.c

31

I suggest to add an empty line here

60

style, blank line, and in many functions below

120

unnecessary parentheses

130

the same here

166

may be use return (netlink_family != NETLINK_ROUTE ? hdr :
rtnl_from_linux(hdr, npt));
?

183

blank line

185

if (out_hdr != NULL)

		memcpy(out_hdr, hdr, hdr->nlmsg_len);

return (out_hdr != NULL);

?

218

the same as above

234

unnecessary parentheses

385

unnecessary parentheses

[melifaro]

Update to reflect netlink KPI changes.