gem5: update to bcf041f257623e5c9e77d35b7531bae59edc0423

This notably allow dynamic linking to work! Move entire README to it.

Also:

- explain what Dhrystone does and run it on gem5 to get DMIPS
- create getprops
- ./test-executables don't test files that start with "tmp."

userland/algorithm/set/generate_io

@@ -21,10 +21,10 @@ random.seed(args.seed)
 input_data = common.LkmcList()
 for i in range(args.size):
     input_data.append(random.randint(args.min, args.max))
-with open('tmp.i', 'w') as i:
+with open(common.consts['tmp_prefix'] + 'i', 'w') as i:
     i.write(str(input_data) + '\n')
 if args.unique:
     input_data = common.LkmcList(set(input_data))
 input_data.sort()
-with open('tmp.e', 'w') as e:
+with open(common.consts['tmp_prefix'] + 'e', 'w') as e:
     e.write(str(input_data) + '\n')