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)

Export symbols that constitute APIs defined by these
modules.

Note that in the case of 'mii' the API is not clearly
defined, and the symbols exported represent a subset
defined by current usage.

Add module directories and makefiles for ncv, nsp, stg and scsi_low
KLD modules.

Submitted-by: takawata