ASan: make copied files in log entries safe at init.

Ensure that if we copy file-names of log entries while startup
logging is active, we free them, but only once startup logging is
disabled, or on shutdown. This is needed to avoid crashes when
we use file-name copying for the Qt message handler.

simgear/debug/logstream.cxx

@@ -139,8 +139,8 @@ public:
         logTimer.stamp();
     }
 
-    virtual void operator()(sgDebugClass c, sgDebugPriority p,
-        const char* file, int line, const std::string& message)
+    void operator()(sgDebugClass c, sgDebugPriority p,
+                    const char* file, int line, const std::string& message) override
     {
         if (!shouldLog(c, p)) return;
 
@@ -402,6 +402,13 @@ public:
     ~LogStreamPrivate()
     {
         removeCallbacks();
+
+        // house-keeping, avoid leak warnings if we exit before disabling
+        // startup logging
+        {
+            std::lock_guard<std::mutex> g(m_lock);
+            clearStartupEntriesLocked();
+        }
     }
 
     std::mutex m_lock;
@@ -448,10 +455,18 @@ public:
         {
             std::lock_guard<std::mutex> g(m_lock);
             m_startupLogging = on;
-            m_startupEntries.clear();
+            clearStartupEntriesLocked();
         }
     }
 
+    void clearStartupEntriesLocked()
+    {
+        std::for_each(m_startupEntries.begin(), m_startupEntries.end(), [](const LogEntry& e) {
+            if (e.freeFilename) free(const_cast<char*>(e.file));
+        });
+        m_startupEntries.clear();
+    }
+
     void run() override
     {
         while (1) {
@@ -475,7 +490,9 @@ public:
                     entry.file, entry.line, entry.message);
             }
 
-            if (entry.freeFilename) {
+            // frrr the filename if required. For startup entries
+            // we wait and do this later
+            if (!m_startupLogging && entry.freeFilename) {
                 free(const_cast<char*>(entry.file));
             }
         } // of main thread loop