[PATCH] Adding diversity for security

[Stephen Crane]

  Discussion of the existing OpenSSL RNG and thread safety brings up another important point: The RNG needs to store state in some thread-local way. Should RNG state be stored in the LLVMContext? I didn't want to mess with LLVMContext without advice from someone who knows the multi-threading roadmap better. It doesn't seem to be the right place, but we need some way to guarantee that only one RNG will be initialized per-thread, rather than using the current static singleton.

http://llvm-reviews.chandlerc.com/D1802