/sys$common/syshlp/helplib.hlb DCE_IDL, DCL Command Interface, QUALIFIERS, /INCLUDE_DIRECTORY  *Conan The Librarian (sorry for the slow response - running on an old VAX)

      /INCLUDE_DIRECTORY [=(pathname [,...])] (default)
      /NOINCLUDE_DIRECTORY

        These qualifiers are equivalent to the -Idirectory
        and -no_def_idir arguments in the universal syntax.