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/init.cpp

@@ -125,7 +125,7 @@ static const char* FEE_ESTIMATES_FILENAME="fee_estimates.dat";
 // shutdown thing.
 //
 
-volatile bool fRequestShutdown = false;
+volatile sig_atomic_t fRequestShutdown = false;
 
 void StartShutdown()
 {

src/util.cpp

@@ -113,7 +113,7 @@ string strMiscWarning;
 bool fLogTimestamps = DEFAULT_LOGTIMESTAMPS;
 bool fLogTimeMicros = DEFAULT_LOGTIMEMICROS;
 bool fLogIPs = DEFAULT_LOGIPS;
-volatile bool fReopenDebugLog = false;
+volatile sig_atomic_t fReopenDebugLog = false;
 CTranslationInterface translationInterface;
 
 /** Init OpenSSL library multithreading support */

src/util.h

@@ -28,6 +28,10 @@
 #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;
@@ -50,7 +54,7 @@ extern std::string strMiscWarning;
 extern bool fLogTimestamps;
 extern bool fLogTimeMicros;
 extern bool fLogIPs;
-extern volatile bool fReopenDebugLog;
+extern volatile sig_atomic_t fReopenDebugLog;
 extern CTranslationInterface translationInterface;
 
 extern const char * const BITCOIN_CONF_FILENAME;