Add a MOD_QUIESCE event for modules. This should return error (EBUSY)
of the module is in use.
MOD_UNLOAD should now only fail if it is impossible (as opposed to
inconvenient) to unload the module. Valid reasons are memory references
into the module which cannot be tracked down and eliminated.
When kldunloading, we abandon if MOD_UNLOAD fails, and if -force is
not given, MOD_QUIESCE failing will also prevent the unload.
For backwards compatibility, we treat EOPNOTSUPP from MOD_QUIESCE as
success.
Document that modules should return EOPNOTSUPP for unknown events.
o start function names in column 1
o sort order of flags in getopt and switch
o don't try to reference progname
o unspam some changes introduced by a 2.2.1-R build box instead of a
-current build box
doc changes:
o document when these commands first appeared
o put email address in angle brakets
o minor mdoc clean up
