[PATCH 2/3] Support unix sockets in -yy option

[Masatake YAMATO]

BTW,

> * linux/unix_diag.h: New file.
> * linux/rtnetlink.h: New file.

Should I bundle linux/unix_diag.h and linux/rtnetlink.h in
my changes? (I included the shrunk version of them in my changes.)

I'm not sure the criteria which .h files are included in strace
or not.

Masatake YAMATO