The all-zero Ed25519 public key is rejected by botan_pubkey_check_key()
when the key is loaded.
Note that Botan 3 requires GCC 11 or CLANG 14, i.e. can't easily be built
on Debian bullseye or Ubuntu 20.04.
The thread-local storage function gets flagged via various botan FFI
functions when using Botan 3, whitelist that instead of all of them.
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