Bypass denormals-to-zero assertion when running under Valgrind

[LuciferDono]

When running Mixxx under Valgrind, the denormals-to-zero verification assertion fails:

DEBUG ASSERT: "doubleMin / 2 == 0.0" in function callbackProcessClkRef()
Denormals to zero mode is not working. EQs and effects may suffer high CPU load

This happens because Valgrind intentionally does not emulate SSE DAZ/FTZ modes and instead uses standard IEEE 754 floating-point behavior, so DBL_MIN / 2 produces a subnormal value rather than 0.0.

This patch detects Valgrind at runtime using the RUNNING_ON_VALGRIND macro from <valgrind/valgrind.h> and skips the assertion in that case. The include is guarded with __has_include so it compiles cleanly on systems without valgrind-dev installed.

Both sounddeviceportaudio.cpp and sounddevicenetwork.cpp are patched since they share the same assertion.

Fixes #16053

[JoergAtGithub]

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[daschuer]

Thank you. The code looks good..
We only waif for confirmation that you have signed the CLA

[LuciferDono]

Thank you. The code looks good.. We only waif for confirmation that you have signed the CLA

Done.

[LuciferDono]

Fixed the pre-commit code style check — adjusted indentation of the VERIFY_OR_DEBUG_ASSERT block and the else branch to satisfy clang-format when nested under the #if/else preprocessor guard.

[daschuer]

Oh I see that unfortunately pre-commit is still complaining. The recommended way to solve it is to run pre-commit locally.
https://github.com/mixxxdj/mixxx/wiki/Using-Git#set-up-automatic-code-checking

The other option is to apply the patch from the faulty workflow run.

[LuciferDono]

Applied the pre-commit patch — the only issue was a long qWarning() string in sounddeviceportaudio.cpp that needed wrapping to satisfy clang-format. Should be green now.

[JoergAtGithub]

LGTM! Thank you!