cairo: depends on recommended x11 for Linuxbrew
cairo: depends on recommended x11 for Linuxbrew

Closes Linuxbrew/linuxbrew#986.

Signed-off-by: Piotr Gaczkowski <46f0c4ed049e7aff30e03b3686f185a0838667df@gmail.com>

maxim-belkin/homebrew-core,rwhogg/homebrew-core,rwhogg/homebrew-core,Linuxbrew/homebrew-core,maxim-belkin/homebrew-core,LinuxbrewTestBot/homebrew-core,LinuxbrewTestBot/homebrew-core,forevergenin/homebrew-core,Linuxbrew/homebrew-core,forevergenin/homebrew-core