我试图在mac OS 10.13上安装Python PIL库。
我了解Pillow，但我希望我的代码可以在仅支持PIL的Google App Engine上运行。
我尝试了sudo pip install pil并得到了：
Collecting pil
Could not find a version that satisfies the requirement pil (from versions: )
No matching distribution found for pil
这让我感到困惑，因为pip search pil会在结果中列出PIL。尝试安装特定版本（如pil==1.1.6）会得到相同的结果。写PIL代替pil也没有帮助。
我也尝试过提供一个明确的网址：sudo pip install http://effbot.org/media/downloads/Imaging-1.1.7.tar.gz但是出现了编译错误：
In file included from _imagingtk.c:19:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.13.sdk/usr/include/tk.h:78:11: fatal error: 'X11/Xlib.h' file not found
# include <X11/Xlib.h>
^~~~~~~~~~~~
1 error generated.
error: command 'cc' failed with exit status 1
如何才能使此安装正常工作？