Remove unused util::detail::rand64bit method

[timwoj]

No description provided.

[timwoj]

@0xxon I merged #2224 earlier not realizing that FreeBSD 12 builds are broken by it. Does this look reasonable as a fix?

[bbannier]

I was wondering why this assertion was here in the first place, and believe it was probably added to ensure that both uint32_t halves of the uint64_t calculated here in below loop are distributed uniformly; if RAND_MAX is less than the maximum uint32_t this is not true anymore.

It looks like the value of RAND_MAX is also used implicitly here which then also causes prng and random_number to return values <=RAND_MAX.

Another issue is that differing RAND_MAX values would not make prng and its users platform-independent anymore like advertised.

TBH, I think this might need a better fix which requires more thinking. You might still want to merge this to unblock CI.

EDIT

Looks like FreeBSD changes the value of RAND_MAX to fix uniformity issues with rand. Arguing that system rand is often of poor quality usually anyway you might able to get away by just removing the static_assert here.

[0xxon]

Looks reasonable for now - but yes, we should probably fix this differently :/

[0xxon]

Thinking about it - this function is in zeek::detail and not used.

I move to just delete it completely.

[timwoj]

I move to just delete it completely.

Sounds good me. I pushed a commit that does that.

[timwoj]

@ckreibich confirmed this method isn't used by any packages in the package repo, so I'll go ahead and push this.