Use int instead of socklen_t

Use int instead of socklen_t

This should work around the compilation problem Johannes Schindelin
and others had on Mac OS/X.

Quoting Linus:

    Any operating system where socklen_t is anything else than "int" is
    terminally broken. The people who introduced that typedef were confused,
    and I actually had to argue with them that it was fundamentally wrong:
    there is no other valid type than "int" that makes sense for it.

Signed-off-by: Junio C Hamano <junkio@cox.net>