Re: [PATCH v2] When building, don't use compiler flags which cause warnings

[Rich Felker <dalias@libc.org>]

On Wed, May 27, 2015 at 04:22:59AM +0200, Shiz wrote:
> > On 26 May 2015, at 21:57, Alex Dowad <alexinbeijing@gmail.com> wrote:
> > 
> > 
> > 
> > On 26/05/15 21:36, Rich Felker wrote:
> > Hmm. -Werror=unknown-warning-option causes configure to disable -Wno-unused-but-set-variable.
> > But it doesn't do anything for other ignored options. It causes problems when building with
> > gcc as well.
> > 
> > This isn't a big issue; I'd suggest it's better not to get stuck on it.
> > 
> > Thanks, AD
> 
> clang also has -Werror=unused-command-line-argument, which I imagine would work better,

I think we _don't_ want this in our final CFLAGS (in fact we may want
the opposite, Wno-...) because it will probably error out on linker
options in CFLAGS or C compiler options in assembler invocations.

But if it detects unknown options, we could use it just at configure
time (if it's supported) to help determine when options are not
supported.

> possibly in tandem with -Werror=unknown-warning option if those gcc problems can be weeded out.

Yes.

Rich