Added executable to make clean.

simmod/ass1/Makefile

@@ -46,5 +46,5 @@ sum: sum.c
 	$(CC) $(FLAGS) -o $* $^
 
 clean:
-	rm -vf *.o *.i *.s fp fd* speed speed.*.* floating_point \
+	rm -vf *.o *.i *.s fp pr fd* speed speed.*.* floating_point \
 		report.pdf *.aux *.log *.toc sum sum.float sum.double