This is the import / export phase.  This process is accomplished as follows:
 
 a) Local definitions are created in each module.  These are entered into the
    local symbol table.
 b) Imports to non-local modules are completely resolved.
 c) Local import/export is performed via a fixpoint:
     1) Export: definitions added in the previous round are filtered by the
        export list and placed in a fresh export list.
     2) Each module imports from the fresh export list of the other modules.
        Any import not already present is placed on a new fresh export list.
    When no fresh exports are generated, the iteration is complete.
 d) Missing exports and imports are checked for.