The randomness is taken from arc4random() which is independent from srand/rand/rand_r,
so there's no need to call srand(). At best, it confuses the reader to think that
there would eventually be a call to rand().
Now that WindowServer broadcasts the system theme using an anonymous
file, we need clients to pledge "recvfd" so they can receive it.
Some programs keep the "shared_buffer" pledge since it's still used for
a handful of things.
