Where oh where are my FreeBSD friends?

[John (J5) Palmieri]

No pressure but I think right now I am blocking on bug#8298[1]

One of the patches is already added and the other ones have comments on
how to fix them.  Two of them are trivially easy.

For the watch issue we just need to pass in a bus context to the watch
function and let the directory watching modules do what they want with
it including ignoring the context entirely in the dnotify module.

For the pthread issue we just need to identify what really needs to be
linked to libpthread and add it there.

The "hard" patch is getting the credential code correct which really
just means cleaning up the HAVE_CMSGCRED and HAVE_LOCAL_CREDS macros to
prefer one method over the other when both are present on a system.

Note that I believe these changes will fix Bug #8363[2] so please no
#ifdef __FreeBSD__.  Yay, two for one.  If we get these patches in and
it doesn't break Solaris I think we will be in good shape for 1.0.

[1] https://bugs.freedesktop.org/show_bug.cgi?id=8298
[2] https://bugs.freedesktop.org/show_bug.cgi?id=8363