[BUG] fd crashes when mimalloc is preloaded with LD_PRELOAD

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• I have read the troubleshooting section and still think this is a bug.

Describe the bug you encountered:

fd crashes when LD_PRELOAD is set to /usr/bin/mimalloc.

Minimal reproduction:

LD_PRELOAD=/usr/bin/mimalloc fd

This may be expected: fd uses jemalloc as its default allocator, so preloading mimalloc may mix allocator implementations or otherwise be unsupported, I thought maybe it would be good to have an issue since I didn't find any.

Describe what you expected to happen:

Either fd should run normally, or it should fail with a clear message that preloading mimalloc is unsupported, rather than crashing.

What version of fd are you using?

10.5.0

Which operating system / distribution are you on?

Arch Linux