fix: vsnprintf usage on macOS

[vaind]

vsnprintf was used incorrectly on macOS (used the windows version) because this code was copied from sentry-unity where it didn't run on mac, only Windows and Linux.

[codecov]

Codecov Report

Attention: 8 lines in your changes are missing coverage. Please review.

Comparison is base (947dac4) 76.43% compared to head (b08727e) 76.45%.

Files	Patch %	Lines
src/Sentry/Platforms/Native/CFunctions.cs	0.00%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3079      +/-   ##
==========================================
+ Coverage   76.43%   76.45%   +0.01%     
==========================================
  Files         351      351              
  Lines       13259    13259              
  Branches     2644     2644              
==========================================
+ Hits        10135    10137       +2     
+ Misses       2447     2446       -1     
+ Partials      677      676       -1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[jamescrosswell]

Could we get some context in the PR summary for what this change is about? Does it relate to an Issue? What was the problem and how does this solve it?

[vaind]

says it all in the PR title, really, but OK, I'll add the same to the description

[jamescrosswell]

says it all in the PR title, really, but OK, I'll add the same to the description

That's helpful. I wasn't aware that vsnprintf was windows only (I've never heard of it before) or that the code we had was copied from Unity. So the whole PR was just mysterious to me.

[vaind]

. I wasn't aware that vsnprintf was windows only

It's not, but we have a windows-only variant defined in the class (IIRC it has different arguments), and since the code switched on linux vs rest of the world (which was just Windows in Unity), macOS was trying to use that windows variant too.

https://github.com/getsentry/sentry-dotnet/pull/3079/files#diff-3d53f32802f41fc554a4ab868d6df5531d920abf89f38886d41e004618fed766R416