你好,当我试图在OSX Lion上使用pip安装pylibmc时出现以下错误: ./_pylibmcmodule.h:42:10: fatal error: 'libmemcached/memcached.h' file not found #include <libmemcached/memcached.h> ^ 1 error generated. error: command 'clang' failed with exit status 1 任何线索如何解决这个问题?