message: Better / more robust error handling
diff: @@ -199,13 +199,7 @@ impl Api for ExternalApi {
  match result {
  1 => Ok(true),
  0 => Ok(false),
  - ptr => {
  - let error = unsafe { consume_string_region_written_by_vm(ptr as *mut Region) };
  - return Err(StdError::generic_err(format!(
  - "verify_secp256k1 error: {}",
  - error
  - )));
  - }
  + x => panic!(format!("unexpected verify_secp256k1 return value: {}", x)),
  }
  }
  