message: More useful error messages
diff: // This file is distributed under the MIT license.
  // See the LICENSE file for details.
  +#include <cstdio>
  #include <stdexcept>
  #include <string>
  @@ -128,7 +129,8 @@ void viewer_sdl2::init(int argc, char** argv)
  if (SDL_Init(SDL_INIT_VIDEO) < 0)
  {
  - printf("Oups\n");
  + printf("Could not initialize initialize SDL: %s\n", SDL_GetError());
  + return;
  }
  impl_->window = SDL_CreateWindow(
  @@ -142,7 +144,8 @@ void viewer_sdl2::init(int argc, char** argv)
  if (impl_->window == nullptr)
  {
  - printf("Oups\n");
  + printf("Could not create SDL window: %s\n", SDL_GetError());
  + return;
  }
  