Added forcing of swap interval on DWM composition.

src/wgl_context.c

@@ -600,12 +600,14 @@ void _glfwPlatformSwapInterval(int interval)
 {
     _GLFWwindow* window = _glfwPlatformGetCurrentContext();
 
+#if !defined(_GLFW_USE_DWM_SWAP_INTERVAL)
     if (_glfwIsCompositionEnabled())
     {
         // Don't enabled vsync when desktop compositing is enabled, as it leads
         // to frame jitter
         return;
     }
+#endif
 
     if (window->wgl.EXT_swap_control)
         window->wgl.SwapIntervalEXT(interval);