我发现macvim如果不从命令行启动, 它的runtimepath选项就会少几个重要的, 直接导致很多报错
具体来说是这些path
/Applications/MacVim.app/Contents/Resources/vim/vimfiles
/Applications/MacVim.app/Contents/Resources/vim/runtime
/Applications/MacVim.app/Contents/Resources/vim/vimfiles/after
所以macvim应当从命令行启动