vc-mode permission problems with recent CVS

[David Abrahams]

I normally have CVSREAD set in my environment so that files are
checked out read-only by default.  After building emacs from the CVS
HEAD as of a few days ago, `C-x v v' on an *un-edited* write-protected
file under source control yields the following messages:

    File is edited but read-only; making it writable
    File is under version-control; use C-x v v to check in/out

The result makes the buffer writable, and even if I kill it the file
will be re-opened with a writable buffer, yet when I try to save the
file I get:

basic-save-buffer-2: Opening output file: permission denied, 
c:/boost/tools/build/build_system.htm

At this point, I have:

    c:\boost\tools\build>attrib build_system.htm
    A          C:\boost\tools\build\build_system.htm
    c:\boost\tools\build>ls -l build_system.htm
    -r--r--r--    1 dave     None        56900 Sep  8 11:05 build_system.htm

A manual "cvs edit build_system.htm" properly changes the files
permissions, so my guess is that vc-mode is mising the fact that the
file is actually unedited and thus never performing the edit command.

Quick workarounds are very much appreciated as this seriously
interferes with my workflow!

TIA,
-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com