Describe the bug
dependency('atomic') does not work on NetBSD and OpenBSD

To Reproduce
use dependency('atomic') on NetBSD or OpenBSD.

Expected behavior
it working.

system parameters

• Is this a [cross build] no.
• what operating system OpenBSD and NetBSD
• what Python version are you using - any
• what meson --version 1.7.0
• what ninja --version N/A

Run-time dependency atomic found: NO (tried system and builtin)
  
  meson.build:145:15: ERROR: Dependency "atomic" not found, tried system and builtin