Fix Issue 11168: attributes for functions in core.stdc.time.

[radcapricorn]

Preferably this needs to be looked at by @WalterBright. May break some third-party code. Phobos tests passed though.

[dlang-bot]

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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	11168	normal	core.stdc.time.asctime() is incorrectly marked as @trusted

Testing this PR locally

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

dub fetch digger
dub run digger -- build "master + druntime#2372"

[thewilsonator]

LGTM, will wait for Walter's review.

[schveiguy]

I re-triggered the build, not sure why the style check failed, I don't see any white space problems.

[thewilsonator]

You can restart individual projects on build kite, please do so it'll be much faster.

[wilzbach]

The style failure is unrelated.

[thewilsonator]

For reference, so is dlang/ci.

[thewilsonator]

Hmm, linux32 OOM'd @radcapricorn you'll need to give this a kick.

[wilzbach]

The auto-tester will automatically restart itself...

[wilzbach]

Besides if it passed before on the auto-tester on the same machine and that's the only failure and it's obviously unrelated, feel free to force merge (though do this with care).

[schveiguy]

@thewilsonator I saw the rebuild button, I pushed it. Sorry ;)

[thewilsonator]

NP, you know for next time ;)