bug#1004: 23.0.60; Error visiting C files

[martin rudalics]

>  emacs -Q
>  C-x C-f foo.c
>
> This produces error messages (see near the end of this report) and
> does NOT enter the C Mode.
[...]
> Eval error in the `c-lang-defconst' for `c-cpp-matchers' in c-mode:
> Eval error in the `c-lang-defconst' for `c-matchers-1' in c-mode:
> File mode specification error: (error "`c-opt-cpp-prefix' got no (prior) value in 
> c-mode (might be a cyclic reference)")

See Bug#913: 23.0.60; File mode specification error for w32.c.

What shall we do about this?

martin