MarsSeed [1] filed a deletion request for texlive-gantt [2]: Broken package. Also [extra] texlive-pictures provides a working version of the same, under the name pgfgantt.sty.
[1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/texlive-gantt/
