Function nginx::EVP_PKEY_meth_set_keygen

pub unsafe extern "C" fn EVP_PKEY_meth_set_keygen(
    pmeth: *mut EVP_PKEY_METHOD, 
    keygen_init: Option<unsafe extern "C" fn(ctx: *mut EVP_PKEY_CTX) -> c_int>, 
    keygen: Option<unsafe extern "C" fn(ctx: *mut EVP_PKEY_CTX, pkey: *mut EVP_PKEY) -> c_int>
)