Fix Issue 20629 - atomicStore does not compile for struct using -m64

[MoonlightSentinel]

No description provided.

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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	20629	normal	atomicStore does not compile for struct using -m64

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "stable + druntime#2971"

[thewilsonator]

This is a regression. Please target stable.

[MoonlightSentinel]

This is a regression. Please target stable.

Sorry, I'll rebase once the CI is done.

[thewilsonator]

The rebase will restart the CI anyway, you may as well change it now.

[MoonlightSentinel]

Done

[thewilsonator]

Thanks!

[MoonlightSentinel]

auto-merge won't work because #2970 is not in stable yet.

Question from the newsgroup:
Will this be included in the new release?

[thewilsonator]

Yes.