Auto merge of #1634 - bitcartel:upstream_8123_race_condition_std_atomic, r=daira

Upstream 8123 race condition

This backports a fix from upstream, with commits applied in sequence:
https://github.com/bitcoin/bitcoin/pull/8004
https://github.com/bitcoin/bitcoin/pull/8112
https://github.com/bitcoin/bitcoin/pull/8123

src/init.cpp

@@ -111,7 +111,7 @@ CClientUIInterface uiInterface; // Declared but not defined in ui_interface.h
 // shutdown thing.
 //
 
-volatile bool fRequestShutdown = false;
+std::atomic<bool> fRequestShutdown(false);
 
 void StartShutdown()
 {

src/util.cpp

@@ -107,9 +107,10 @@ bool fPrintToDebugLog = true;
 bool fDaemon = false;
 bool fServer = false;
 string strMiscWarning;
-bool fLogTimestamps = false;
-bool fLogIPs = false;
-volatile bool fReopenDebugLog = false;
+bool fLogTimestamps = DEFAULT_LOGTIMESTAMPS;
+bool fLogTimeMicros = DEFAULT_LOGTIMEMICROS;
+bool fLogIPs = DEFAULT_LOGIPS;
+std::atomic<bool> fReopenDebugLog(false);
 CTranslationInterface translationInterface;
 
 /** Init OpenSSL library multithreading support */

src/util.h

@@ -18,6 +18,7 @@
 #include "tinyformat.h"
 #include "utiltime.h"
 
+#include <atomic>
 #include <exception>
 #include <map>
 #include <stdint.h>
@@ -28,6 +29,10 @@
 #include <boost/signals2/signal.hpp>
 #include <boost/thread/exceptions.hpp>
 
+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 +50,7 @@ extern bool fServer;
 extern std::string strMiscWarning;
 extern bool fLogTimestamps;
 extern bool fLogIPs;
-extern volatile bool fReopenDebugLog;
+extern std::atomic<bool> fReopenDebugLog;
 extern CTranslationInterface translationInterface;
 
 /**