[rfc] Check that GCC accepts the given -W option

[Andrew Cagney]

Andrew Cagney wrote:
> 
> Hello,
> 
> The attatched tweeks the configury so that it checks that a -W option is
> valid before trying to use it.
> Look ok?
> 
>         Andrew
> 
>   ------------------------------------------------------------------------
> Thu May 11 21:52:55 2000  Andrew Cagney  <cagney@b1.cygnus.com>
> 
>         * configure.in (WERROR_CFLAGS): Check that GCC accepts a -W option
>         before using it.

FYI,

I've checked in a cleanup of this patch - it also reports the results of
the probe.

	Andrew