Update examples for testing modules

examples/dom/linear_gradient.cpp

@@ -1,13 +1,21 @@
 // Copyright 2023 Arthur Sonzogni. All rights reserved.
 // Use of this source code is governed by the MIT license that can be found in
 // the LICENSE file.
+#ifndef FTXUI_BUILD_MODULES
 #include <ftxui/dom/elements.hpp>  // for bgcolor, operator|, operator|=, text, center, Element
 #include <ftxui/dom/linear_gradient.hpp>  // for LinearGradient::Stop, LinearGradient
 #include <ftxui/screen/screen.hpp>        // for Full, Screen
+#endif 
+
 #include <memory>                         // for allocator, shared_ptr
 
+#ifndef FTXUI_BUILD_MODULES
 #include "ftxui/dom/node.hpp"  // for Render
 #include "ftxui/screen/color.hpp"  // for Color, Color::DeepPink1, Color::DeepSkyBlue1, Color::Yellow, ftxui
+#else
+import ftxui.dom;
+import ftxui.screen;
+#endif
 
 int main() {
   using namespace ftxui;