[llvm] [libc][bazel] Add Bazel rules for rand/srand functions. (PR #159617)

[Joseph Huber via llvm-commits]

jhuber6 wrote:

If this is only for internal it would probably be better to make an internal randomness function that takes the state as an argument instead of it being a global. I already do that in a few places.

https://github.com/llvm/llvm-project/pull/159617