Speculative Linux build fix, not using itoa (#246)

imgui_demo.cpp

@@ -959,7 +959,7 @@ void ImGui::ShowTestWindow(bool* opened)
                     if (n > 0) ImGui::SameLine();
                     ImGui::PushID(n + line * 1000);
                     char num_buf[16];
-                    const char* label = (!(n%15)) ? "FizzBuzz" : (!(n%3)) ? "Fizz" : (!(n%5)) ? "Buzz" : itoa(n, num_buf, 10);
+                    const char* label = (!(n%15)) ? "FizzBuzz" : (!(n%3)) ? "Fizz" : (!(n%5)) ? "Buzz" : (sprintf(num_buf, "%d", n), num_buf);
                     float hue = n*0.05f;
                     ImGui::PushStyleColor(ImGuiCol_Button, ImColor::HSV(hue, 0.6f, 0.6f));
                     ImGui::PushStyleColor(ImGuiCol_ButtonHovered, ImColor::HSV(hue, 0.7f, 0.7f));