(vc-sccs-latest-on-branch-p): Always return t; we

(vc-sccs-latest-on-branch-p): Always return t; we
don't support anything else under SCCS yet.
(vc-sccs-update-changelog): Dummy implementation that
simply signals an error.
(vc-sccs-state-heuristic): Use
file-ownership-preserved-p.
(vc-sccs-workfile-unchanged-p): Fix call to
vc-do-command.
(vc-sccs-state-heuristic): Don't use file-writable-p.
(vc-sccs-workfile-unchanged-p): Fix parenthesis.
(vc-sccs-print-log, vc-sccs-diff): Insert in the current buffer.
(vc-sccs-workfile-unchanged-p): Rewritten.
(vc-sccs-diff): Remove optional arg CMP.
(vc-sccs-state): Call vc-workfile-unchanged-p, not the
SCCS-specific function.
(vc-sccs-state): Fix obviously wrong parenthesis.
(vc-sccs-state-heuristic): Use file-writable-p instead of
comparing userids.
(vc-sccs-checkout): Use `unless'.
(vc-sccs-state): Use with-temp-buffer.
(vc-sccs-workfile-version): Use with-temp-buffer and new
vc-parse-buffer and don't bother setting the property.
(vc-sccs-add-triple): Use with-current-buffer and
find-file-noselect.
(vc-sccs-lookup-triple): New vc-parse-buffer and turn cond -> if.
 Merge in
code from vc-sccs-hooks.el.
(vc-sccs-release, vc-sccs-system-release): Remove.  Don't require
'vc anymore.
(vc-sccs-responsible-p): Use expand-file-name instead of concat
and file-directory-p instead of file-exists-p.
(vc-sccs-check-headers): Simplify the regexp.
(vc-sccs-responsible-p, vc-sccs-register): Use
`vc-sccs-search-project-dir' instead of `vc-sccs-project-dir'.
(vc-sccs-header): New var.
(vc-sccs-rename-file): Renamed from
vc-sccs-record-rename.  Use `find-file-noselect' rather than
`find-file' and call `vc-rename-master' to do the actual move.
(vc-sccs-diff): Remove unused `backend' variable.
(tail): Provide vc-sccs.
(vc-sccs-checkout): Removed call to
vc-file-clear-masterprops.  If writable, set vc-state to 'edited
rather than user login name.
 Require 'vc and 'vc-sccs-hooks.
(vc-sccs-register-switches): New var, copied off of vc-rcs-hooks.
(vc-sccs-latest-on-branch-p): Add a `FIXME' for a call to the
unknown `vc-latest-version' function.  It should probably refer to
vc-workfile-version or somesuch, but it's very unclear to me and I
don't have SCCS to test things.
(vc-sccs-steal-lock): Renamed from `vc-sccs-steal'.
(vc-BACKEND-responsible-p): New
functions.
(vc-BACKEND-register): Renamed from `vc-BACKEND-admin'.  Removed
query option.  Redocumented.
(vc-sccs-diff): Function changed name from
`vc-backend-diff'.  This makes `vc-diff' work.
(vc-sccs-release): Doc fix.
(vc-sccs-admin): Added the query-only option as
required by the vc.el file.
(vc-sccs-latest-on-branch-p): Function added.
(vc-sccs-diff): Function added.
(vc-sccs-checkout): Added function `vc-sccs-checkout'.
 Require vc when compiling.
(vc-sccs-print-log, vc-sccs-assign-name, vc-sccs-merge)
(vc-sccs-check-headers, vc-sccs-steal, vc-sccs-uncheck)
(vc-sccs-revert)
(vc-sccs-checkin, vc-sccs-logentry-check): New functions (code
from vc.el).
(vc-sccs-add-triple, vc-sccs-record-rename)
(vc-sccs-lookup-triple): Moved from vc.el and renamed.
(vc-sccs-admin): Doc fix.
(vc-admin-sccs): Added from vc.el
(vc-sccs-system-release):
Renamed from vc-sccs-backend-release.
(vc-sccs-release): Moved from vc.el.
(vc-sccs-backend-release): New function.