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)

Revive files which were pulled from the vendor branch only to be
removed on HEAD, but which are part of the GDB 6.1.1 import. This
makes HEAD identical to the vendor branch, for better or for
worse.