Log Message:
Update to 1.18

Upstream changes:
1.18

    - Added more documentation about empty_port()

1.17

    commit 0f4510d83ae2f2ce112288c64289fa36d32865b3
    Author: Christian Walde <walde.christian@googlemail.com>
    Date:   Sat Jul 28 07:04:40 2012 +0200

        fix port checking on Win32 by performing it in another process

        On Win32 fork is emulating by creating another thread in the same process.
        This leads to a possible bug/race condition when a server tries to open a
        port and listen on it, while in the same process a client tries to connect
        to the same port. This manifests by the accept call of the server failing
        with an error of "Bad file descriptor".

        This is easily fixed by having another process perform the port checking,
        since that will not interfere with the internals.