Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Remove UFS-specific parts from mount(8).
For mounting UFS, all mount options are passed directly to nmount(),
without any UFS-specific logic.

- Minor fixes to raise WARNS level to 6.
- Teach the mount program to call the nmount() syscall directly
- Preserve existing method of calling mount() for UFS, until we clean things
up.
- Preserve existing method of forking and calling external mount programs for
mfs, msdosfs, nfs, nfs4, ntfs, nwfs, nullfs, portalfs, reiserfs, smbfs,
udf, umapfs, unionfs
- devfs, linprocfs, procfs, ext2fs call nmount() syscall directly, since
that is all those external mount programs were doing

Reviewed by: phk
Discussed on: arch

Switch from K&R-style C prototypes to ISO/ANSI-style C prototypes.
Make prototype in extern.h match prototype in mount_ufs.c

o __P removed
o main prototype removed

$Id$ -> $FreeBSD$

Moved getmntops() stuff back to mntopt.h so that it is visible in other
mount utilities.

Forgot to cvs add this new file.