timschumi [1] filed a orphan request for citra-git [2]:

The package is currently not buildable without modifications, due to missing build-time dependencies and wrong commands in the PKGBUILD file. The issue was first reported on 2018-06-06 in the packages' comments (along with a suitable fix), but the current maintainer neither responded nor fixed the issue to this date.

[1] https://aur.archlinux.org/account/timschumi/ [2] https://aur.archlinux.org/pkgbase/citra-git/