Function EverCrypt_HKDF_hkdf_extract 

pub unsafe extern "C" fn EverCrypt_HKDF_hkdf_extract(
    a: Spec_Hash_Definitions_hash_alg,
    prk: *mut u8,
    salt: *mut u8,
    saltlen: u32,
    ikm: *mut u8,
    ikmlen: u32,
)