Added a new CIF operator "not-interact" which is complementary to

"interact", because it was trivially easy to implement and saves
processing vs. doing the same thing with two templayers and an
"and-not" operator.

cif/CIFgen.c

@@ -4752,6 +4752,13 @@ cifInteractingRegions(
 		}
 	}
 
+	/* op->co_client is an invert bit indicating the rule is "not-interact",
+	 * so invert the sense of "interacts".  Then the non-interacting regions
+	 * will be kept and the interacting regions will be discarded.
+	 */
+	if (op->co_client == (ClientData)1)
+	    interacts = (interacts) ? FALSE : TRUE;
+
 	/* Clear the tiles that were processed in this set, first copying them	*/
 	/* to the destination if this region was found to be interacting with	*/
 	/* op->co_paintMask (op->co_cifMask)					*/ 

cif/CIFtech.c

@@ -110,6 +110,7 @@ cifTechFreeStyle(void)
 			    case CIFOP_BBOX:
 			    case CIFOP_MAXRECT:
 			    case CIFOP_BOUNDARY:
+			    case CIFOP_INTERACT:
 				/* These options use co_client to hold a single	*/
 				/* integer value, so it is not allocated.	*/
 				break;
@@ -1096,6 +1097,11 @@ CIFTechLine(
 	newOp->co_opcode = CIFOP_BRIDGELIM;
     else if (strcmp(argv[0], "interact") == 0)
 	newOp->co_opcode = CIFOP_INTERACT;
+    else if (strcmp(argv[0], "not-interact") == 0)
+    {
+	newOp->co_opcode = CIFOP_INTERACT;
+	newOp->co_client = (ClientData)1;
+    }
     else
     {
 	TechError("Unknown statement \"%s\".\n", argv[0]);