(We do this unconditionally, since we still need it for tortls.c)

This is meant for use when encrypting the current time within the
period in order to get a monotonically increasing revision counter
without actually revealing our view of the time.

This scheme is far from the most state-of-the-art: don't use it for
anything else without careful analysis by somebody much smarter than
I am.

See ticket #25552 for some rationale for this logic.

This is largely conjectural, based on online documentation for NSS
and NSPR.

These are now part of crypto_init.c.  The openssl-only parts now
live in crypto_openssl_mgt.c.

I recommend reviewing this patch with -b and --color-moved.

When it is set, include the NSS headers and libraries as
appropriate.  Doesn't actually use them yet, though.

Now the address-set code and the digest-set code share the same
backend.

Closes ticket 26510

I am calling the crypto library "crypt_ops", since I want
higher-level crypto things to be separated from lower-level ones.
This library will hold only the low-level ones, once we have it
refactored.