VMS Help CC, Messages, DEFINOTHER3  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 Message        This declaration of "<name>" specifies a different
                thread-local attribute than a declaration in another
                module of this compilation at <where>.

 Description    In a compilation where interfile optimization has
                been selected (-ifo on UNIX, /PLUS_LIST_OPTIMIZE on
                OpenVMS), the compiler has detected a name with
                external linkage declared thread-local in one module
                and not thread-local in another.  This can lead to
                unexpected results at runtime.

 User Action    Modify one the declarations to make the thread-local
                attributes match.