Eliminate data races for strMiscWarning and fLargeWork*Found.

This moves all access to these datastructures through accessor functions
 and protects them with a lock.

src/util.cpp

@@ -108,6 +108,7 @@ bool fDebug = false;
 bool fPrintToConsole = false;
 bool fPrintToDebugLog = true;
 
+CCriticalSection cs_warnings;
 string strMiscWarning;
 bool fLargeWorkForkFound = false;
 bool fLargeWorkInvalidChainFound = false;
@@ -813,6 +814,36 @@ std::string CopyrightHolders(const std::string& strPrefix)
     return strCopyrightHolders;
 }
 
+void SetMiscWarning(const std::string& strWarning)
+{
+    LOCK(cs_warnings);
+    strMiscWarning = strWarning;
+}
+
+void SetfLargeWorkForkFound(bool flag)
+{
+    LOCK(cs_warnings);
+    fLargeWorkForkFound = flag;
+}
+
+bool GetfLargeWorkForkFound()
+{
+    LOCK(cs_warnings);
+    return fLargeWorkForkFound;
+}
+
+void SetfLargeWorkInvalidChainFound(bool flag)
+{
+    LOCK(cs_warnings);
+    fLargeWorkInvalidChainFound = flag;
+}
+
+bool GetfLargeWorkInvalidChainFound()
+{
+    LOCK(cs_warnings);
+    return fLargeWorkInvalidChainFound;
+}
+
 std::string GetWarnings(const std::string& strFor)
 {
     string strStatusBar;
@@ -820,6 +851,8 @@ std::string GetWarnings(const std::string& strFor)
     string strGUI;
     const string uiAlertSeperator = "<hr />";
 
+    LOCK(cs_warnings);
+
     if (!CLIENT_VERSION_IS_RELEASE) {
         strStatusBar = "This is a pre-release test build - use at your own risk - do not use for mining or merchant applications";
         strGUI = _("This is a pre-release test build - use at your own risk - do not use for mining or merchant applications");