Yves/wellrng512a support

[demerphq]

This patch sequence adds support for building Perl with WELLRNG512a, a modern random number generator by Matsumoto (co-creator of the Mersenne Twister), L’Ecuyer (a major RNG researcher), and Panneton. It is considered superior to the MT family of RNG's. It is suitable for 32 bit and 64 bit builds.

See:

https://en.wikipedia.org/wiki/Well_equidistributed_long-period_linear http://www.iro.umontreal.ca/~lecuyer/myftp/papers/wellrng.pdf

You can access the new behavior by adding -Accflags=-DPERL_USE_WELL512A_RNG to your favourite Configure invocation. Eg:

./Configure -Dusethreads -Doptimize="-g3 -ggdb3" -d -Dusedevel -Dcc=ccache\ gcc -Dld=gcc -DDEBUGGING -A ccflags=-DPERL_USE_WELL512A_RNG

• This set of changes requires a perldelta entry, and it is NOT currently included.
• This set of changes requires additional documentation and especially it needs direct recognition of the creators as well as the author of the implementation that this patch sequence contains. It is from Chris Lomont via his paper here: https://lomont.org/papers/2008/Lomont_PRNG_2008.pdf
• This set of changes is currently in DRAFT status to stimulate discussion and for review purposes. It includes incidental changes that will be submitted independently in other MR's.