The two "functions" that isc/safe.h declared before were actually simple
defines to matching OpenSSL functions. The downside of the approach was
enforcing all users of the libisc library to explicitly list the include
path to OpenSSL and link with -lcrypto. By hiding the specific
implementation into the private namespace changing the defines into
simple functions, we no longer enforce this. In the long run, this
might also allow us to switch cryptographic library implementation
without affecting the downstream users.
4183. [cleanup] Use timing-safe memory comparisons in cryptographic
code. Also, the timing-safe comparison functions have
been renamed to avoid possible confusion with
memcmp(). [RT #40148]
