Fix #203
On some x86_64 hardware the RDRAND instruction returns 64bits of entropy from an on-chip random number generator. RDRAND is not recommended as an exclusive source of entropy for cryptographic applications. https://en.wikipedia.org/wiki/RdRand
Ref #74
- zynq_parallella - zynq_zedboard - zynq_zc706 - zynq_zc702