bug#46563: file-system declarations do not currently support cifs mounts

[Katherine Cox-Buday]

With a file-system declartion of:

#+BEGIN_SRC scheme
(file-system
 (mount-point "/home/user/foo")
 (device "//server/foo")
 (type "cifs")
 (options "username=user,vers=2.0,uid=1000,gid=988")
 (check? #f)
 (create-mount-point? #t)
 (mount-may-fail? #t))
#+END_SRC

I get the following error:

#+BEGIN_EXAMPLE
$ sudo guix system reconfigure /etc/config.scm
/etc/config.scm:97:9: error: device '//server/foo not found: No such file or 
directory
#+END_EXAMPLE

With =cifs-utils= installed, I would expect this to work.