Fix Backtrace define error for Windows

src/main.cpp

@@ -40,6 +40,7 @@
 QQmlDebuggingEnabler enabler;
 #endif
 
+#if !defined(Q_OS_WINDOWS)
 #if HAVE_BACKTRACE_SYMBOLS_FD
 #include <csignal>
 #include <execinfo.h>
@@ -92,6 +93,7 @@ registerSignalHandlers()
         std::signal(SIGABRT, &stacktraceHandler);
 }
 
+#endif
 #else
 
 // No implementation for systems with no stacktrace support.