Examples: example_glut_opengl2: Fixed compilation issue (#6361)

examples/example_glut_opengl2/main.cpp

@@ -108,6 +108,7 @@ void MainLoopStep()
     ImGui_ImplOpenGL2_NewFrame();
     ImGui_ImplGLUT_NewFrame();
     ImGui::NewFrame();
+    ImGuiIO& io = ImGui::GetIO();
 
     // 1. Show the big demo window (Most of the sample code is in ImGui::ShowDemoWindow()! You can browse its code to learn more about Dear ImGui!).
     if (show_demo_window)
@@ -148,7 +149,6 @@ void MainLoopStep()
 
     // Rendering
     ImGui::Render();
-    ImGuiIO& io = ImGui::GetIO();
     glViewport(0, 0, (GLsizei)io.DisplaySize.x, (GLsizei)io.DisplaySize.y);
     glClearColor(clear_color.x * clear_color.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w, clear_color.w);
     glClear(GL_COLOR_BUFFER_BIT);