Unexpand the tag, remove the fbsd:nokeywords property and add the
svn:keywords property. This should eliminate the gratuituous diffs
that appear on these files in projects branches.
Sponsored by: The FreeBSD Foundation
(x86 assembler optimization disabled for now because it
requires the new .cfi_* directives that is not supported
by base system binutils).
MFC after: 1 week
