Function in3_sys::in3_create_signer

pub unsafe extern "C" fn in3_create_signer(
    sign: in3_sign, 
    prepare_tx: in3_prepare_tx, 
    wallet: *mut c_void
) -> *mut in3_signer_t

create a new signer-object to be set on the client. the caller will need to free this pointer after usage.