XBPS includes the following software from third parties for
internal use in the code:

- queue.h from NetBSD (include/queue.h).
- package pattern matching code from NetBSD (lib/dewey.c lib/match.c).
- strlcat and strlcpy functions from OpenBSD (lib/compat/strlc{at,cpy}.c)
- libfetch-2.31 from NetBSD (lib/fetch).
- portableproplib-0.4.1 (lib/portableproplib) from
  http://code.google.com/p/portableproplib