[Buildroot] [PATCH] support/dependencies: require at least CMake 3.8

[Yann E. MORIN <yann.morin.1998@free.fr>]

On 2018-12-31 18:00 +0100, Yann E. MORIN spake thusly:
> On 2018-12-31 17:47 +0100, Thomas Petazzoni spake thusly:
> > On Mon, 31 Dec 2018 17:44:54 +0100, Yann E. MORIN wrote:
> > > On 2018-12-31 17:26 +0100, Thomas Petazzoni spake thusly:
> > > > The json-for-modern-cpp package unfortunately now requires CMake >=
> > > > 3.8, so we need to bump our requirement from 3.1 to 3.8. If the host
> > > > doesn't have a CMake >= 3.8, Buildroot will build its own host-cmake
> > > > package.  
> > > 
> > > The upstream commit that bumped the requirement to cmake 3.8 states:
> > > 
> > >     Using target_compile_features to specify C++ 11 standard
> > >     https://github.com/nlohmann/json/commit/73cc5089e33ea950b6677e19ee7ec656c9bcf985
> > > 
> > > However, target_compile_features has been available even since 3.1 at
> > > least:
> > > 
> > >     https://cmake.org/cmake/help/v3.1/command/target_compile_features.html
> > > 
> > > I'll kick-start a build with a patched json-for-modern-cpp, to see if we
> > > can stay on 3.1.
> > Thanks! It would be a lot nicer! Do you have a CMake 3.1 installation
> > readily available ?
> Now I have! ;-)

And indeed, that is sufficient to stick to 3.1. I'll send a proper patch
and submit it upstream too.

Regards,
Yann E. MORIN.

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