diff --git a/Mac/mwerks/mwerks_carbonplugin_config.h b/Mac/mwerks/mwerks_carbonplugin_config.h
index 7c949c9460c..0d2fc7c89a2 100644
--- a/Mac/mwerks/mwerks_carbonplugin_config.h
+++ b/Mac/mwerks/mwerks_carbonplugin_config.h
@@ -6,6 +6,7 @@
 #define TARGET_API_MAC_CARBON 1
 #define TARGET_API_MAC_CARBON_NOTYET 1 /* Things we should do eventually, but not now */
 #define WITHOUT_FRAMEWORKS /* Use old-style Universal Header includes, not Carbon/Carbon.h */
+#define USE_TOOLBOX_OBJECT_GLUE	/* Use glue routines for accessing PyArg_Parse/Py_BuildValue helpers */
 
 /* #define USE_GUSI1		/* Stdio implemented with GUSI */
 #define USE_GUSI2		/* Stdio implemented with GUSI */
diff --git a/Mac/mwerks/mwerks_plugin_config.h b/Mac/mwerks/mwerks_plugin_config.h
index 27717d05efb..9aa494188e7 100644
--- a/Mac/mwerks/mwerks_plugin_config.h
+++ b/Mac/mwerks/mwerks_plugin_config.h
@@ -8,7 +8,8 @@
 #define USE_GUSI
 #endif
 #define WITH_THREAD		/* Use thread support (needs GUSI 2, not GUSI 1) */
-#define WITHOUT_FRAMEWORKS /* Use old-style Universal Header includes, not Carbon/Carbon.h */
+#define WITHOUT_FRAMEWORKS	/* Use old-style Universal Header includes, not Carbon/Carbon.h */
+#define USE_TOOLBOX_OBJECT_GLUE	/* Use glue routines for accessing PyArg_Parse/Py_BuildValue helpers */
 #define USE_MSL			/* Use MSL libraries */
 #ifdef USE_MSL
 #define MSL_USE_PRECOMPILED_HEADERS 0	/* Don't use precomp headers: we include our own */
diff --git a/Mac/mwerks/mwerks_shared_config.h b/Mac/mwerks/mwerks_shared_config.h
index afd7210b449..05e92933506 100644
--- a/Mac/mwerks/mwerks_shared_config.h
+++ b/Mac/mwerks/mwerks_shared_config.h
@@ -28,6 +28,7 @@
 /* #define USE_ZLIB		/* Include the zlib module */
 #define USE_APPEARANCE	/* Enable Appearance support */
 #define WITHOUT_FRAMEWORKS /* Use old-style Universal Header includes, not Carbon/Carbon.h */
+#define USE_TOOLBOX_OBJECT_GLUE /* Call toolbox object converters indirectly */
 
 #define USE_MSL_MALLOC	/* Disable private malloc. Also disables next two defines */
 #ifndef USE_MSL_MALLOC
diff --git a/Mac/mwerks/mwerks_shcarbon_config.h b/Mac/mwerks/mwerks_shcarbon_config.h
index ec4e5c438c2..26a9b141edf 100644
--- a/Mac/mwerks/mwerks_shcarbon_config.h
+++ b/Mac/mwerks/mwerks_shcarbon_config.h
@@ -33,6 +33,7 @@
 /* #define USE_ZLIB		/* Include the zlib module */
 #define USE_APPEARANCE	/* Enable Appearance support */
 #define WITHOUT_FRAMEWORKS /* Use old-style Universal Header includes, not Carbon/Carbon.h */
+#define USE_TOOLBOX_OBJECT_GLUE /* Call toolbox object converters indirectly */
 
 #define USE_MSL_MALLOC	/* Disable private malloc. Also disables next two defines */
 #ifndef USE_MSL_MALLOC