WELL prng instead of M-M.
Merge pull request #5 from 1500100900/prng_well

WELL prng instead of M-M.
Missing prototype.
Cast from function call of type 'int' to non-matching type 'float'.
Unused macro definitions.
Variable pexit may be uninitialized when used at line 5753.
Remove some unnecessary objects and rename others so that -Wshadow becomes useful.