Add newer versions of EASTL and update install script.

[galorojo]

There's 2 "interesting" things in this change (aside from the boring "just add new versions" part):

• Adding recursive: false: EASTL suffered from a cyclical submodule dependency fiasco (see Circular submodule dependency causes recursive clones or submodule updates to fail electronicarts/EASTL#301), I actually don't know how this worked before. When I tried to do ce_install install eastl locally I'd hit the infinite recursion issue, this no longer occurs if we opt out of a recursive clone.
• Adding some steps to run in after_stage_script: starting in version 3.21.23 EASTL moved away from submodule dependencies to potentially fix the circular dependency fiasco (see electronicarts/EASTL@c530255) and replaced them with CMake's FetchContent functionality. This script is an attempt to pull out the only non-test dependency (EABase) and put it in EASTL's include path so the parts of EASTL which do #include <EABase/foo.h> still work.

Tested running ce_install install eastl in a local instance of CE and things work as expected with all versions.

The corresponding change in compiler-explorer is compiler-explorer/compiler-explorer#6816

[galorojo]

It is slightly unfortunate that we now run cmake even on the versions for which it is not necessary (the ones not using FetchContent), hopefully this isn't a big deal but I'm happy to hear about alternatives if anyone thinks of one.

[mattgodbolt]

Which versions? We can solve that by making a new section and only applying the after_stage_script to those. I'll try out in a branch and merge if I can get it to work.

[galorojo]

Hi @mattgodbolt,

We can solve that by making a new section and only applying the after_stage_script to those.

Thanks for your comment, I've changed the code a bit follow what benchmark is doing and this seems to work properly without doing any unnecessary work. I'm not sure if that's exactly what you were suggesting, or if there's a better way, let me know what you think.

[galorojo]

Converting this to a draft given that EASTL might have to go back to submodules after all. (see electronicarts/EASTL#539). Apologies for the churn.

[mattgodbolt]

Let me know when/if you're ready and I can help with the changes (ping me on Discord or here)

[galorojo]

I still don't know what will happen with future versions of EASTL wrt going back to submodules, but either way I think this can be merged so we get up to date versions of EASTL working.