`brew tap` will cause error

[tan-wei]

Thanks for this repo. But I encounter the problem :

→ brew tap lincerely/tools
==> Tapping lincerely/tools
Cloning into '/usr/local/Homebrew/Library/Taps/lincerely/homebrew-tools'...
remote: Enumerating objects: 87, done.
remote: Counting objects: 100% (87/87), done.
remote: Compressing objects: 100% (66/66), done.
remote: Total 87 (delta 28), reused 77 (delta 18), pack-reused 0
Receiving objects: 100% (87/87), 11.46 KiB | 5.73 MiB/s, done.
Resolving deltas: 100% (28/28), done.
Error: Invalid formula: /usr/local/Homebrew/Library/Taps/lincerely/homebrew-tools/Formula/sent.rb
sent: Unsupported special dependency :x11
Error: Cannot tap lincerely/tools: invalid syntax in tap!