Use arc4random on macOS. Previously we were relying on /dev/urandom, which on macOS uses the Yarrow PRNG with a 160 bit security limit. New macOS systems use AES for arc4random, so it is safer to make the switch.
Use arc4random on macOS. Previously we were relying on /dev/urandom, which on macOS uses the Yarrow PRNG with a 160 bit security limit. New macOS systems use AES for arc4random, so it is safer to make the switch.

jsfierro/jfpg,jsfierro/jfpg,jsfierro/jfpg,an0dos/jfpg,an0dos/jfpg