Allow building wxGTK3 with Broadway backend.

Use GDK_WINDOWING_BROADWAY to fix compilation with it.

Closes #14469.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72075 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk/utilsgtk.cpp

@@ -504,3 +504,17 @@ wxGUIAppTraits::GetStandardCmdLineOptions(wxArrayString& names,
 }
 
 #endif // __UNIX__
+
+#ifdef GDK_WINDOWING_BROADWAY
+
+bool wxLaunchDefaultApplication(const wxString& document, int flags)
+{
+    return false;
+}
+
+bool wxDoLaunchDefaultBrowser(const wxString& url, int flags)
+{
+    return false;
+}
+
+#endif