[openssl-dev] Improving OpenSSL default RNG

[Salz, Rich]

I am very interested in cleaning this area up.  We still do care about Netware, OS/2, and VMS; I don't think we care about pre-XP Windows.

We have broader portability issues than boringSSL does, so my thoughts on threading are different:  two builds, either "not threaded" or "use native system threads" and internally use an API that is a very small thin layer per-OS.