Log Message:
- Update tcptrace to 6.6.1
- Remove FreeBSD header from pkgsrc Makefile
- ok'ed snj@/wiz@

>From the ChangeLog:
- Fixed the processing of duplicate ACKs as in the BSD stack to count towards
  the 3 dupacks required for fast-retransmit.
- Fixed the bug in processing IPv6 extension headers in ipv6.c:gethdrlength()
  based on the patch sent by Thomas Bohnert.
- Added dsack counter to long output format and dsack sample input and output
- Fixed bug in the calculation of the "avg win adv" field, so that now avg.
  falls in between min and max.
- Changes made to make gcc-3.3 make lesser warnings with tcptrace.
- Made the --csv/--tsv/--sv options' implementation better.
- Fixed a bug in traffic module, so that the number of open connections are
  printed correct in the traffic_stats.dat file, even without giving
  the -C option.
- Included the code to recognize Endace ERF (Extensible Record Format), sent
  by Jesper Peterson.
- Included the code to recognize the PPP (Point-to-Point) input file format,
  sent by Yann Samama.
- Fixing the bug with filtering connections based on hostname/portname with
  the -f option.
- Included the code to generate PF file with '-c' option. Error messages are
  made more logical when generating error messages for unsupported input and
  captured file formats.
- Applied patch from Ulisses Alonso Camaro that lets SYN segments following
  zero window advertisements from the opposite direction *not* be treated
  as window probes. Also fixed a compilation problem due to the previous
  patch by Jitesh (moved the "static int count=0" line to the beginning of
  trace_done() function in trace.c).
- Fixed bunch of gcc3.3.1 warnings in erf.c (unused variable warning), netm.c,
  ns.c (dereferencing type-punned pointer warnings).
- Fixed the typo(?) that made us have a #ifndef __WIN32 to #ifdef __WIN32 in
  ipv6.h for the in6_addr structure definition.
- Patching in changes to mod_http.c making it more robust to print
  information in cases where connections get closed with RST instead of
  FINs and other trivia based on Yufei Wang's patch.
- Applying the patch courtesy John Heffner that displays a yellow rwnd line
  in owin plots. Also adding --showrwinline option to control the yellow
  rwnd line, in case it gets annoying.
- Also fixing trivia (type conversions for certain uint to int, etc.) in
  output.c to keep gcc3.3 from warning on MacOSX 10.3.
- All the changes you see above in the 6.4.x series are part of the release
  6.6.0.
- Includes a bugfix by Ramani, that restored the old semantics of the
  SameConn() and WhichDir() functions and includes
  new functions AVL_CheckHash() and AVL_CheckDir() to support the AVL tree
  hash-bucket implementation.
- Includes a fix to ns.c to correctly read port numbers; added
  functionality to track LEAST variables and reno LEAST algorithm to trace.c;
  added isRTO() in rexmit.c : all by Wes.