WIP: MCST Elbrus initial port

[a1batross]

Needed some changes in crnlib and zstd.
Probably upgrading to upstream zstd or using a system provided library would be better

• Compiles
• Runs
• Works

[a1batross]

dimgui_impl.cpp file needs decoupling to separate files or just compiling imgui into a static library.

Overall, it just smells bad when code have #include <something.cpp> rather than compiling files one by one, potentially leveraging concurrency.

[feliwir]

I'm currently in the process of replacing the insource dependencies - so the compilation should work with upstream versions of the libraries. See #15

[autious]

@feliwir does your upstreaming work collide with this pull request, or do you recommend that we pull this in?

@a1batross, i agree on the #include <f.cpp> thing.

[shinymerlyn]

Overall, it just smells bad when code have #include <something.cpp> rather than compiling files one by one, potentially leveraging concurrency.

This is not necessarily true. Linking time etc can dominate on some platforms. One of the reasons why "unity builds" are a thing.
But in this case the include wasn't done in order to improve performance, so I say do whatever way makes sense.

[feliwir]

@autious
It does not collide with my work, but to me those libraries are thirdparty software - we should not modify it. Ideally we want to be able to just pull a new version of those libraries without breaking anything. However when we customize these libraries every update will be painful or we will just forget to readd the feature.

If something inside those libraries does not compile on any platform it should be fixed upstream and we can then upgrade to the version containing the fix.

E.g. for ZStd do a PR for that file inside the official repository: https://github.com/facebook/zstd/blob/v1.5.0/lib/common/compiler.h#L154