Debian: Avoid install-info errors on "make install"?

[Kai Großjohann]

When compiling Emacs from the CVS sources, then doing "make install",
I get errors (warnings?) like this:

* Ada mode: (ada-mode). Emacs mode for editing Ada code.
install-info(/home/kai/sw/emacs-21.0/info/ada-mode): replacing existing dir 
entry for `ada-mode'
cp: cannot create regular file `/var/backups/infodir.bak': Permission denied
install-info(/home/kai/sw/emacs-21.0/info/ada-mode): couldn't backup 
/home/kai/sw/emacs-21.0/info/dir in /var/backups/infodir.bak: No such file or 
directory

Suggestions?
-- 
A turnip curses Elvis