[PATCH] "address.GetPort() != 0" assertion for helpers on FreeBSD

Hello,

    Some v3.3 and trunk helpers are broken on FreeBSD and possibly some
other non-Linux OSes. Squid using ssl_crtd, URL rewriter, and possibly
other helpers asserts on startup:

  assertion failed: comm.cc:800: "address.GetPort() != 0"

Our src/defines.h #include file requires sys/socket.h on FreeBSD for
AF_UNIX to be defined in time for IPC_* tests. I suspect a similar but
not-yet-exposed dependency exists for O_TEXT and friends.

The attached patch fixes the AF_UNIX bug in my tests. A better long-term
fix is welcomed.

Thank you,

Alex.