I tried building a very recent version of emacs from CVS (actually
from the git mirror at git://git.sv.gnu.org/emacs.git) on Vista, and
it fails as you can see in the attachment.  The very same commit
builds and runs fine on XP.  Any idea what's wrong?  I started with a
very clean directory, by which I mean: I ran "git-clean -dxf", which
deletes all files that aren't known to git; and I ran "git status" to
ensure that all of the remaining files were identical to their
versions in the repository.
The executive summary is:
    Compiling gnus/nnvirtual.el

    In toplevel form:
    gnus/nnvirtual.el:34:1:Error: Symbol's value as variable is void:
\300\214\300\214

... and many similar mysterious errors during byte-compilation.