Upgrade yocto submodule and publish new SDK version

[barthalion]

Could you bump Poky version used to build this runtime and release new SDK? Currently it ships CMake 3.3.0 (released in July 2015), while some projects require at least 3.6. Yocto Morty contains 3.6.1.

[alexlarsson]

In general we can't just update the yocto version, thats like "just updating" the distro. Runtimes are meant to be long-term ABI stable.

That said, we can reconsider updating individual packages, and in particular, for sdk-only packages the stability requirements are a bit more lenient (i.e. we will not break existing apps, only make old apps un-rebuildable).

Whats the overall stance on backwards compat in the cmake project?

[barthalion]

I'm aware of ABI meaning of versions. By publishing new SDK I meant making it '1.5' or '2.0' version.

I'm not CMake expert but I just reverted the change that bumped the CMake version requirement and the project continues to build, so I guess it's highly dependent on the upstream.

[alexlarsson]

I meant, how backwards compat is cmake itself. If we updated it in the sdk, would it break the build for things that used the old one.

[barthalion]

Looking at some questions on Stackoverflow, there are some incompatibilities that may require changes in projects. I guess it means that upgrade should be postponed for new runtime release.