GP-2391 added evaluation of return address, allow thunking addresses to externals. Added new arem thunk pattern.

Ghidra/Processors/68000/src/main/java/ghidra/app/plugin/core/analysis/Motorola68KAnalyzer.java

@@ -304,6 +304,11 @@ public class Motorola68KAnalyzer extends ConstantPropagationAnalyzer {
 				return instruction.getMinAddress().equals(targetSwitchAddr);
 			}
 
+			@Override
+			public boolean evaluateReturn(Varnode retVN, VarnodeContext context, Instruction instruction) {
+				return false;
+			}
+			
 			@Override
 			public Long unknownValue(VarnodeContext context, Instruction instruction,
 					Varnode node) {