libmpd changed their versioning scheme from the previous 0.20.0
to this 11.8.17 which is apparently like going to 0.20.95, except
that they wanted to match the version numbering on their main
project gmpc. This version compiles with llvm, gcc-4.2.1, and
clang from XCode 4.0.2 on x64 10.6.8. See their sourceforge files:
* http://sourceforge.net/projects/musicpd/files/ClosesHomebrew/homebrew#7750.
Signed-off-by: Charlie Sharpsteen <source@sharpsteen.net>