mmap has serveral potential issues and we do not really need it, so
changing to use the normal system file interface is better.
Signed-off-by: Csaba Kiraly <csaba.kiraly@gmail.com>
Minimal working version with lots of error checks and corrections
still needed.
- using Bearssl RSA code through libp2p
- with selecteble BigInt library for experimentation
Signed-off-by: Csaba Kiraly <csaba.kiraly@gmail.com>
