如何让Kivy 1.9.1或1.9.2在OSX 10.12.2上使用SDL2而不是pygame？

试图让Kivy在由Brew安装的python 2.7.13下的OSX 10.12.2上使用SDL2而不是pygame.我运行以下命令来安装依赖项.它们看起来安装得很好,因为"酿造医生"会恢复干净.

brew install sdl2 sdl2_image sdl2_ttf sdl2_mixer gstreamer
pip install -I Cython==0.23

然后我尝试了从源代码编译的1.9.2-dev0和1.9.1版本的Kivy,尝试使用SDL.我也尝试了pip install kivy,而不是来自repo的最新代码,这些尝试都没有让Kivy识别出SDL2.

git clone http://github.com/kivy/kivy
cd kivy
USE_SDL2=1 make force
USE_OSX_FRAMEWORKS=0 sudo pip install -e kivy

bash-3.2$ KIVY_WINDOW=sdl2 KIVY_IMAGE=sdl2 KIVY_CLIPBOARD=sdl2 KIVY_TEXT=sdl2 python main.py
[INFO   ] [Logger      ] Record log in /Users/dancaron/.kivy/logs/kivy_17-01-23_107.txt
[INFO   ] [Kivy        ] v1.9.2-dev0
[INFO   ] [Python      ] v2.7.13 (default, Jan 23 2017, 19:04:34)
[GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.42.1)]
[INFO   ] [Factory     ] 193 symbols loaded
[INFO   ] [Image       ] Providers:  (img_imageio, img_tex, img_dds, img_pygame, img_ffpyplayer, img_pil, img_gif ignored)
[CRITICAL] [App         ] Unable to get any Image provider, abort.

如何让Kivy使用SDL2？