Added code to handle the special case of a zero-length move.

Added more tests of memcpy() and memmove().

testcode/lib/pce/Makefile

@@ -1,3 +1,4 @@
+.PHONY: all clean test
 
 all: conio.pce
 
@@ -5,9 +6,7 @@ conio.pce: conio.c
 	../../../bin/cl65 -t pce conio.c --mapfile conio.map -o conio.pce
 
 clean:
-	$(RM) conio.pce
-	$(RM) conio.map
+	$(RM) conio.o conio.pce conio.map
 
 test: conio.pce
 	mednafen -force_module pce conio.pce
-