GUI: Fixing some minor Export dialog bugs (texture option disabled on export or failing to save mesh without extension set)

guilib/src/ExportCloudsDialog.h

@@ -116,6 +116,7 @@ private:
 	void setSaveButton();
 	void setOkButton();
 	void enableRegeneration(bool enabled);
+	void updateTexturingAvailability(bool isExporting);
 
 private:
 	Ui_ExportCloudsDialog * _ui;