32bit compat NFS server and PMC syscalls

[Martin Husemann <martin%duskware.de@localhost>]

I've been looking at adding the missing things to compat/netbsd32
recently, mainly to make the default N32 userland on mips64 more usefull
and able to run our full test suite.

Most missing pieces are just oversights/lazyness and easy to fill in.

However, I wonder about

 a) nfssvc (i.e. the nfsd kernel part) - does it make sense to use that?
    Alternatively we could build the nfsd binary as N64 on mips64 (like
    we need to do for some of the essential kvm grovelers)

 b) pmc_get_info/pmc_control
    These are undocumented syscalls apparently used by the pmc(1) tool.
    Is this interface (still) usefull and MI enough to be worth supporting?


Martin