Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

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.