[ic] Shipping address form for non_US countries

[Dr. Michael Streubel]

Consider the shipping address part of the checkout form in foundation.
For country US, the postal code field has appropriate error behaviour:
It behaves like any required field.

However, for non-US countries, it suddenly tolerates being empty,
which is fatal for a casual user without account, because for the 
auto-created
user the zip code is to be used  as a password.

Does anyone have a clue how and where to fix that?

Michael