Examples: SDL: Fixed unused variable warning on non-Windows platforms (#626)

examples/sdl_opengl3_example/imgui_impl_sdl_gl3.cpp

@@ -330,6 +330,8 @@ bool    ImGui_ImplSdlGL3_Init(SDL_Window* window)
     SDL_VERSION(&wmInfo.version);
     SDL_GetWindowWMInfo(window, &wmInfo);
     io.ImeWindowHandle = wmInfo.info.win.window;
+#else
+    (void)window;
 #endif
 
     return true;

examples/sdl_opengl_example/imgui_impl_sdl.cpp

@@ -218,6 +218,8 @@ bool    ImGui_ImplSdl_Init(SDL_Window* window)
     SDL_VERSION(&wmInfo.version);
     SDL_GetWindowWMInfo(window, &wmInfo);
     io.ImeWindowHandle = wmInfo.info.win.window;
+#else
+    (void)window;
 #endif
 
     return true;