fReopenDebugLog and fRequestShutdown should be type sig_atomic_t

This allows access as an atomic variable in the presence
of async interrupts.

See issue #7433 for more details
fixes: #7433

src/util.h

@@ -28,6 +28,14 @@
 #include <boost/signals2/signal.hpp>
 #include <boost/thread/exceptions.hpp>
 
+#ifndef WIN32
+#include <signal.h>
+#endif
+
+static const bool DEFAULT_LOGTIMEMICROS = false;
+static const bool DEFAULT_LOGIPS        = false;
+static const bool DEFAULT_LOGTIMESTAMPS = true;
+
 /** Signals for translation. */
 class CTranslationInterface
 {
@@ -45,7 +53,7 @@ extern bool fServer;
 extern std::string strMiscWarning;
 extern bool fLogTimestamps;
 extern bool fLogIPs;
-extern volatile bool fReopenDebugLog;
+extern volatile sig_atomic_t fReopenDebugLog;
 extern CTranslationInterface translationInterface;
 
 /**