From Mathias Froehilch, "

On OpenThreads win32 implementation we unconditionally unlock a mutex in the
destructor. That happens even if the mutex was not locked before.
When running a osg application within microsofts application verifier, that
software checks tells me that we should not unlock an unlocked mutex.

When I look at the posix threads mutex implementation, which does no unlock in
the destructor and where it is illegal to destroy a locked mutex, I conclude
that it is not needed for an OpenThreads::Mutex to do that unlock in the
win32 Mutex destructor.

Thus this patch based on rev 9358 removes that additional unlock in the win32
mutex implementations destructor."

src/OpenThreads/win32/Win32Mutex.cpp

@@ -93,7 +93,6 @@ Mutex::Mutex() {
 // Use: public.
 //
 Mutex::~Mutex() {
-    unlock();
     delete static_cast<Win32MutexPrivateData*>(_prvData);
 }
 //----------------------------------------------------------------------------