feat: use standard atomics and call_once

[codecov-commenter]

Codecov Report

Attention: 5 lines in your changes are missing coverage. Please review.

Comparison is base (51e7a43) 58.75% compared to head (de1f93d) 64.50%. Report is 1 commits behind head on master.

Files	Patch %	Lines
src/signalhandler.cc	0.00%	4 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1026 +/- ## ========================================== + Coverage 58.75% 64.50% +5.75% ========================================== Files 18 18 Lines 2560 3130 +570 Branches 918 1327 +409 ========================================== + Hits 1504 2019 +515 - Misses 707 726 +19 - Partials 349 385 +36 ```

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