Remove all but one '#ifdef undef' which is to be looked at.
[Rich Salz]
+ *) Clean up calling of xxx_free routines.
+ Just like free(), fix most of the xxx_free routines to accept
+ NULL. Remove the non-null checks from callers. Save much code.
+ [Rich Salz]
+
*) Experimental support for a new, fast, unbiased prime candidate generator,
bn_probable_prime_dh_coprime(). Not currently used by any prime generator.
[Felix Laurie von Massenbach <felix@erbridge.co.uk>]