Removed three lines of code that were meant to be a test of how

much performance can be sped up if the DRC process can be
interrupted at much finer intervals.  Unfortunately, the method
cannot work without an additional method to ensure that magic is
immediately aware when a search routine has been entered
recursively and to then break out of the search and clean up
after itself.  For now, I am just commenting out the code so that
magic isn't unstable.

drc/DRCbasic.c

@@ -501,9 +501,22 @@ DRCBasicCheck (celldef, checkRect, clipRect, function, cdata)
 
 #ifdef MAGIC_WRAPPER
 	/* Execute pending Tcl events, so the DRC process doesn't block.    */
+
+	/* WARNING:  This code cannot be enabled until some method is
+	 * worked out to determine if any event resulted in a change
+	 * to the DRC check plane which would invalidate the current
+	 * search.  If so, the search must end immediately and the
+	 * area being checked must be reinstated.  The code was added
+	 * to see how it speeds up the response time of magic when
+	 * some of the DRC rules are compute-intensive.  It speeds up
+	 * performance enough that it is worthwhile to implement the
+	 * method just mentioned.
+	 */
+	#if 0
 	UndoEnable();
 	while (Tcl_DoOneEvent(TCL_DONT_WAIT));
 	UndoDisable();
+	#endif
 #endif
     }
     drcCifCheck(&arg);