Remove SRP and Kerberos support from libssl. These are complex protocols
all on their own and we can't effectively maintain them without using them,
which we don't. If the need arises, the code can be resurrected.
OpenBSD has_SC_CLK_TCK.

ok miod@
Kill memory debug calls that are now noops. While here, nuke an #if 0 and
a unnecessary NULL check before free.

ok miod@
During the great e_os.h nukathon we stopped pulling in <sys/filio.h> via
the ifdef maze, meaning that FIONBIO was no longer defined. This removes
non-blocking I/O support from s_{client,server,time}.

Remove all FIONBIO ifdefs and import <sys/ioctl.h>, renabling -nbio.

ok miod@
Repair BIO_socket_nbio operation.

ok miod@
Sort and group includes.