Disable built-in NaN handler through hidden setting (#4787)

* Disable built-in NaN handler through hidden setting

* Reuse code

include/MixHelpers.h

@@ -33,6 +33,10 @@ namespace MixHelpers
 
 bool isSilent( const sampleFrame* src, int frames );
 
+bool useNaNHandler();
+
+void setNaNHandler( bool use );
+
 bool sanitize( sampleFrame * src, int frames );
 
 /*! \brief Add samples from src to dst */

include/SetupDialog.h

@@ -142,6 +142,7 @@ private:
 	bool m_MMPZ;
 	bool m_disableBackup;
 	bool m_openLastProject;
+	bool m_NaNHandler;
 	bool m_hqAudioDev;
 	QString m_lang;
 	QStringList m_languages;