into modules. By and large this commit:
- shuffles header files and ifdefs
- splits code out where necessary to be modular
- adds module glue for each of the components
- adds/replaces hooks for things that can be installed at runtime
nfs_bootstatic() to abort with EOPNOTSUPP. This allows a callback to
say that there is no bootstatic config, and the next NFS boot method should
be tried.
a driver selectable callback function. This is used in the Xen port to
allow controlling the domain's network setup from the domain building
environment at domain creation (vs. having to maintain/change this on a
dhcp server). The Xen network driver parses a command line passed in
from the domain builder.
