--- vmd-1.8.6/src/TclTextInterp.C.orig	2009-02-02 23:24:27.000000000 +0300
+++ vmd-1.8.6/src/TclTextInterp.C	2009-02-02 23:35:33.000000000 +0300
@@ -100,7 +100,9 @@
 
 TclTextInterp::TclTextInterp(VMDApp *vmdapp)
 : app(vmdapp) {
-  
+#if 0
+	Tcl_InitMemory(interp); // enable Tcl memory debugging features when compiled with TCL_MEM_DEBUG
+#endif
   interp = Tcl_CreateInterp();
   commandPtr = Tcl_NewObj();
   Tcl_IncrRefCount(commandPtr);
@@ -310,8 +312,16 @@
     callLevel++;
     Tcl_RecordAndEvalObj(interp, commandPtr, 0);
     callLevel--;
-
+#if TCL_MINOR_VERSION >= 5
+	if (Tcl_IsShared(commandPtr)) {
+		Tcl_DecrRefCount(commandPtr);
+		commandPtr = Tcl_NewObj();
+		Tcl_IncrRefCount(commandPtr);
+	}
+#else
+// XXX this crashes Tcl 8.5.[46] with an internal panic
     Tcl_SetObjLength(commandPtr, 0);
+#endif
     
     // if ok, send to stdout; if not, send to stderr
     Tcl_Obj *resultPtr = Tcl_GetObjResult(interp);
@@ -388,8 +398,16 @@
     if (app->exitFlag) break;
 
     Tcl_RecordAndEvalObj(interp, cmdPtr, 0);
+#if TCL_MINOR_VERSION >= 5
+	if (Tcl_IsShared(cmdPtr)) {
+		Tcl_DecrRefCount(cmdPtr);
+		cmdPtr = Tcl_NewObj();
+		Tcl_IncrRefCount(cmdPtr);
+	}
+#else
+ // XXX this crashes Tcl 8.5.[46] with an internal panic
     Tcl_SetObjLength(cmdPtr, 0);
-
+#endif
     // XXX what's this here for?
     app->display_update();