Fix some compiler warnings

source/backend/CarlaUtils.cpp

@@ -581,7 +581,7 @@ public:
         return fLastReadLine;
     }
 
-    bool msgReceived(const char* const msg) noexcept
+    bool msgReceived(const char* const msg) noexcept override
     {
         if (fCallbackFunc != nullptr)
         {

source/utils/CarlaPipeUtils.cpp

@@ -1379,6 +1379,9 @@ bool CarlaPipeServer::startPipeServer(const char* const filename,
 #endif
 
     return false;
+
+    // maybe unused
+    (void)size;
 }
 
 void CarlaPipeServer::stopPipeServer(const uint32_t timeOutMilliseconds) noexcept