Use template function instead of void* parameter

This change gets rid of -Wthread-safety-attributes warning spam.

src/sync.cpp

@@ -219,12 +219,15 @@ static bool LockHeld(void* mutex)
     return false;
 }
 
-void AssertLockHeldInternal(const char* pszName, const char* pszFile, int nLine, void* cs)
+template <typename MutexType>
+void AssertLockHeldInternal(const char* pszName, const char* pszFile, int nLine, MutexType* cs)
 {
     if (LockHeld(cs)) return;
     tfm::format(std::cerr, "Assertion failed: lock %s not held in %s:%i; locks held:\n%s", pszName, pszFile, nLine, LocksHeld());
     abort();
 }
+template void AssertLockHeldInternal(const char*, const char*, int, Mutex*);
+template void AssertLockHeldInternal(const char*, const char*, int, RecursiveMutex*);
 
 void AssertLockNotHeldInternal(const char* pszName, const char* pszFile, int nLine, void* cs)
 {