Fix warning '_CRT_SECURE_NO_WARNINGS': macro redefinition

[Jackarain]

No description provided.

[Flamefire]

Thanks for the PR. I'm wondering in which situation you encounter this issue. Those files changed are internal source files and the build scripts don't define those defines. So how do you run into the warning?

[Jackarain]

Thanks for reviewing this.
The issue stems from the add_definitions(-D_CRT_SECURE_NO_WARNINGS) used in main projects, causing a macro redefinition warning with your files. My PR aims to resolve this for smoother integration.

https://github.com/Jackarain/proxy/actions/runs/7319843765/job/19938178701#step:3:1403

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (a9cea73) 99.47% compared to head (3c4e045) 99.47%.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #177   +/-   ##
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  Coverage    99.47%   99.47%           
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  Files           34       34           
  Lines         3447     3447           
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  Hits          3429     3429           
  Misses          18       18           

Files	Coverage Δ
src/cstdio.cpp	100.00% <ø> (ø)
src/cstdlib.cpp	91.66% <ø> (ø)
test/test_system.cpp	100.00% <ø> (ø)