Build History for pull/255

rdseed: 100 retries, rdrand: 10 retries

cpu_rng_bootstrap: use rdrand if rdseed fails. if rdseed fails, take 512 times rdrand. if rdrand fails 512 times (* 10 from the RETRIES in C), fail

cpu_rng_bootstrap: use rdrand if rdseed fails. if rdseed fails, take 512 times rdrand. if rdrand fails 512 times (* 10 from the RETRIES in C), fail

entropy: provide rdrand and rdseed calls and failures

use memcpy instead of manual copying

use memcpy instead of manual copying

Handle CPU_RNG failures in OCaml: - Previously, a return value of "0" was treated specially, but rdrand/rdseed may return 0! - If there's a failure in rdrand/rdseed during cpu_rng_bootstrap, raise an exception - If there's a failure during the periodic reseeding (timer initiated feeding of all pools), ignore it (for now!?)