lib/crc32: expose whether the lib is really optimized at runtime
Make the CRC32 library export a function crc32_optimizations() which
returns flags that indicate which CRC32 functions are actually executing
optimized code at runtime.
This will be used to determine whether the crc32[c]-$arch shash
algorithms should be registered in the crypto API. btrfs could also
start using these flags instead of the hack that it currently uses where
it parses the crypto_shash_driver_name.
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20241202010844.144356-4-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>