Log Message:
Update darkstat to 3.0.540.
Patch provided by MAINTAINER, Bartosz Kuzma via PR 34158.

Changes from 3.0.524 to 3.0.540
 - Fix build against old libpcap (thanks Claudio)
 - Fix build on AIX (thanks Andreas)
 - Fix build warnings on NetBSD (thanks Bartosz)
 - Deny writes to BPF socket (thanks Can)
 - Reverse-resolve IPs less aggressively.
 - Free up the DNS queue as we process it.
 - Fix dns_reply silliness.
 - Web: tweak the look of the top bar.
 - Web: update total packets and bytes as part of graph update.
 - Decode DLT_LINUX_SLL (ippp0 on Linux),
   patch courtesy of Ingo Bressler

pkgsrc specific changes:
 - /var/empty has marked obsolete by etcupdate so I've changed
   chroot dir for darkstat to ${PREFIX}/share/darkstat/chroot.
 - patch-aa add support for DLT_PPP_SERIAL (for NetBSD only)
   and DLT_PPP devices.