Use LOCK macros for non-recursive locks

Instead of std::unique_lock.

src/threadinterrupt.h

@@ -5,6 +5,8 @@
 #ifndef BITCOIN_THREADINTERRUPT_H
 #define BITCOIN_THREADINTERRUPT_H
 
+#include <sync.h>
+
 #include <atomic>
 #include <chrono>
 #include <condition_variable>
@@ -28,7 +30,7 @@ public:
 
 private:
     std::condition_variable cond;
-    std::mutex mut;
+    CWaitableCriticalSection mut;
     std::atomic<bool> flag;
 };