Replace the old OpenSSL PRNG by direct use of arc4random_buf(), keeping the

Replace the old OpenSSL PRNG by direct use of arc4random_buf(), keeping the
existing RAND interfaces unchanged.

All interfaces allowing external feed or seed of the RNG (either from a file
or a local entropy gathering daemon) are kept for ABI compatibility, but are
no longer do anything.

While the OpenSSL PRNG was required 15+ years ago when many systems lacked
proper entropy collection, things have evolved and one can reasonably assume
it is better to use the kernel (system global) entropy pool rather than trying
to build one's own and having to compensate for thread scheduling...

<RANT>
Whoever thought that RAND_screen(), feeding the PRNG with the contents of the
local workstation's display, under Win32, was a smart idea, ought to be banned
from security programming.
</RANT>

ok beck@ deraadt@ tedu@