pktanon: add a patch to fix build failure.

```brew install pktanon``` failed with messages:

~~~diff
==> Downloading http://www.tm.uka.de/software/pktanon/download/pktanon-1.4.0-dev.tar.gz
Already downloaded: /Library/Caches/Homebrew/pktanon-1.4.0.tar.gz
==> ./configure --prefix=/usr/local/Cellar/pktanon/1.4.0
==> make install
                sleep (1);
                ^
1 error generated.
make: *** [Timer.o] Error 1
make: *** Waiting for unfinished jobs....
~~~

This PR fixes the issue by adding a patch to complement a missing "#include" line.
Not reported yet.
(PktAnon project http://www.tm.uka.de/software/pktanon/ does not seem to have a bug-tracker.)