Using a cross-platform glob implementation on all platforms

Hi internals,

Following some discussion in GH-15564 about providing a cross-platform
glob implementation, I've done the work to make the implementation used
on Windows (which is from OpenBSD) the default on all platforms. You can
see it at GH-18164. CI is currently passing with this.

The code change is pretty minimal beyond cleanup. There are some things
that might need to be changed (i.e. if we want to support system glob
implementations), but those can be put off the table. It does simplify
some documentation concerns as well. I raise the question to internals
to see if this should be done or if it's big enough to merit an RFC.

Regards,
Calvin