Fix deadlock issue with mingw in async logger

include/spdlog/details/mpmc_blocking_q.h

@@ -32,37 +32,31 @@ public:
 
     // try to enqueue and block if no room left
     void enqueue(T &&item)
-    {
+    {        
-        {
+        std::unique_lock<std::mutex> lock(queue_mutex_);
-            std::unique_lock<std::mutex> lock(queue_mutex_);
+        pop_cv_.wait(lock, [this] { return !this->q_.full(); });
-            pop_cv_.wait(lock, [this] { return !this->q_.full(); });
+        q_.push_back(std::move(item));        
-            q_.push_back(std::move(item));
+		push_cv_.notify_one();
-        }
-        push_cv_.notify_one();
     }
 
     // enqueue immediately. overrun oldest message in the queue if no room left.
     void enqueue_nowait(T &&item)
-    {
+    {        
-        {
+        std::unique_lock<std::mutex> lock(queue_mutex_);
-            std::unique_lock<std::mutex> lock(queue_mutex_);
+        q_.push_back(std::move(item));       
-            q_.push_back(std::move(item));
+		push_cv_.notify_one();
-        }
-        push_cv_.notify_one();
     }
 
     // try to dequeue item. if no item found. wait upto timeout and try again
     // Return true, if succeeded dequeue item, false otherwise
     bool dequeue_for(T &popped_item, std::chrono::milliseconds wait_duration)
-    {
+    {        
-        {
+		std::unique_lock<std::mutex> lock(queue_mutex_);
-            std::unique_lock<std::mutex> lock(queue_mutex_);
+		if (!push_cv_.wait_for(lock, wait_duration, [this] { return !this->q_.empty(); }))
-            if (!push_cv_.wait_for(lock, wait_duration, [this] { return !this->q_.empty(); }))
+		{
-            {
+			return false;
-                return false;
+		}
-            }
+		q_.pop_front(popped_item);        
-            q_.pop_front(popped_item);
-        }
         pop_cv_.notify_one();
         return true;
     }