Cmake - Remove pow & some libm & math.h handling

[vincele]

Fixes issue: #1043

Code Changes:

• Have the PR Validation Tests been run? See https://github.com/vegastrike/Vega-Strike-Engine-Source/wiki/Pull-Request-Validation
• This is a documentation change only

Issues:

• PR'ed to let CI run on different systems, was OK on void-linux, x86_64, musl libc

Purpose:

• What is this pull request trying to do? Removing old cruft from cmake config
• What release is this for? Next one
• Is there a project or milestone we should apply this to? Next one

[stephengtuggy]

I'm not so sure this is a good idea. I suspect there was a good reason why this block was there, and the reason probably still applies.

[vincele]

Still it built on all the CI platforms (BTW, there's no BeOS in there, but having this diversity (different linuxes, macos & windows is really good !).

I think pow() is such a basic math function that missing it would be fairly obvious, I don't think this would induce subtle bugs. But with FP math, we never know what lurks in there...

[royfalk]

Let's keep the discussion in #1043.

[royfalk]

@BenjamenMeyer can you add your two cents here?
I'd prefer to reach some consensus here if possible.

In short, @vincele and I think pow checks can be removed.
The C++ documentation thinks this has been a part of the standard since a long time ago. Possibly C++03. Certainly Pre C++11.
@stephengtuggy advises caution.

[BenjamenMeyer]

I advise caution for the time being while we confirm platforms.

Let me get #1041 finished & merged, and we can test and do some research on this in the meantime.

[BenjamenMeyer]

Blocking this per #1051 (comment) until I at least get that work done.