This is mainly useful for implementing things like explicit_bzero(), to guarantee memory is zeroed before freeing it(free() makes no guarantees about the conte

This is mainly useful for implementing things like explicit_bzero(), to guarantee memory is zeroed before freeing it(free() makes no guarantees about the contents of freed memory). This is hugely important for discarding things like private keys. Up until now, safely implementing explicit_bzero() has depended on various hacks that a new compiler version might drag out from under you. This should end the "arms race".