If someone could update the following text:
libdispatch on FreeBSD 2009-10-21 The libdispatch library is available in the FreeBSD ports collection for experimental use on FreeBSD 9.x. Several kqueue kernel enhancements are planned for FreeBSD 8.1 in order to allow the libdispatch port to be used on FreeBSD 8.x as well.
Information is available on the FreeBSD wiki about installing the libdispatch, llvm-devel, and compiler-rt ports allowing full use of the blocks extension to C with libdispatch.
libdispatch is now appropriate for (we think) production use as of FreeBSD 8.1; to use it, just install the libdispatch port or package and the rest should follow automatically. I've just updated the FreeBSD wiki page, wiki.freebsd.org/GCD, to reflect this as well. (If the above turns out not to work so well, I also accept bug reports!) Robert