Library /sys$common/syshlp/macro$dwci.hlb options, generation, enable, global  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  Click on the Undefined Assumed External button to
  direct the assembler to treat all undefined symbols in
  the assembly as external symbols.  When the button is
  off, any undefined symbol that is not listed in an
  .EXTERNAL directive causes an assembly error.

  Equivalent qualifier (DCL interface):

     /[NO]ENABLE=GLOBAL
     /[NO]DISABLE=GLOBAL