[Buildroot] [PATCH 2/4] toolchain: check the SSP option is known

[yann.morin at orange.com]

Arnout, All,

On 2019-03-12 09:49 +0100, Arnout Vandecappelle spake thusly:
> On 12/03/2019 07:41, yann.morin at orange.com wrote:
> > Arnout, All,
> > 
> > On 2019-03-12 07:18 +0100, MORIN Yann TGI/OLS spake thusly:
> >> On 2019-03-12 01:25 +0100, Arnout Vandecappelle spake thusly:
> > [--SNIP--]
> >>>  I notice that in vlc.mk, we have
> >>> ax_cv_check_cflags___fstack_protector_strong=$(if $(BR2_TOOLCHAIN_HAS_SSP),yes,no)
> >> I'll check what vlc really wants it for (e.g. strong, all, regular?),
> >> fix and send a patch.
> > 
> > So, vlc already depends on gcc >= 4.9 anyway, so there will always have
> > support for fstack-protctor-strong, and this legacy wart can be removed
> > now, I guess.
> 
>  Not at all! gcc >= 4.9 doesn't guarantee SSP availability, only that if SSP is
> available, then -fstack-protector=strong will work. So the check is correct
> because vlc depends on gcc >= 4.9.

Ah, yes, I see now. That's because SSP is a shared feature between the
compiler and the C library, right?

So that check does indeed make sense as it is, even though it is not
really obvious...

Thanks!

Regards,
Yann E. MORIN.

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