The random number generation function from libc was useful for very basic 
purposes but hasn't kept up with the times.

There are many options to provide a Portable Random Number Generator: one 
of the most popular and easiest to implement was designed by B.A Wichmann
and I.D Hill in 1982.

We chose to implement the newer 2006[1] algorithm which is better suited
modern platforms and passes DIEHARD and TestU01 - Big Crush tests.

Use of libc's rand() has been completely eliminated by using preexisting
rtl/random support to generate the initial seeds.

Special thanks to orcmid@ for discussion and testing.

Reference:

[1] B. A. Wichmann and Hill, Generating good pseudorandom numbers,
Computational Statistics & Data Analysis, Volume 51 Issue 3,
December, 2006, Pages 1614-1622.