fix windows build when the module is in different dll than the library defs

dtool/src/interrogate/interfaceMakerPythonNative.cxx

@@ -1148,7 +1148,7 @@ write_module_support(ostream &out, ostream *out_h, InterrogateModuleDef *def) {
 
   out << "  {NULL, NULL, 0, NULL}\n" << "};\n\n";
 
-  out << "struct LibraryDef " << def->library_name << "_moddef = {python_simple_funcs, BuildInstants};\n";
+  out << "EXPORT_THIS struct LibraryDef " << def->library_name << "_moddef = {python_simple_funcs, BuildInstants};\n";
   if (out_h != NULL) {
     *out_h << "extern struct LibraryDef " << def->library_name << "_moddef;\n";
   }

dtool/src/interrogate/interrogate_module.cxx

@@ -112,7 +112,7 @@ int write_python_table_native(ostream &out) {
   pset<std::string >::iterator ii;
   for(ii = libraries.begin(); ii != libraries.end(); ii++) {
     printf("Referencing Library %s\n", (*ii).c_str());
-    out << "extern LibraryDef " << *ii << "_moddef;\n";
+    out << "IMPORT_THIS LibraryDef " << *ii << "_moddef;\n";
   }
 
   out << "\n"