[Libguestfs] [PATCH nbdkit v2 0/6] New ones plugin and evil filter

This addresses most of the issues from the review of v1 here: https://listman.redhat.com/archives/libguestfs/2023-May/031520.html * The filter now only handles 1e-12 <= P <= 1/8. Probabilities outside this range are treated as 0% or 100% respectively. The reasons are given in the code and man page, but basically are to do with stopping things from blowing up. The restriction is not essential - it might be fixed in future. I also added tests for small and large probabilities. * I did *not* change probability parsing or the "inf/nan" etc case or return the numerator and denominator separately. The parsing could be changed/fixed later. The API/ABI could not be changed, but I'm unconvinced that returning two numbers instead of one does anything except push the problem elsewhere. * A new commit is added to make <ispowerof2.h> log_2_bits work on 64 bit ints on all platforms. I tested this inside a 32 bit mock. * Add more debugging, and in particular print the seed. * Use Python to count bits instead of scary shell script. * When comparing subsets in the tests, make sure they contain a stuck bit. * Use '**' for exponentiation consistently. * Various other comments / typos / etc fixed and some improvements to the man page. * Retest. Now I must get back to doing real work! Rich.