MarsSeed [1] filed a deletion request for makemkv-libaacs [2]:

Bogus, broken package.
But if it did work, it would still not be needed or useful to keep, as
it would just replace extra repo's libaacs with a potentially
incompatible foreign binary library.

[1] https://aur.archlinux.org/account/MarsSeed/
[2] https://aur.archlinux.org/pkgbase/makemkv-libaacs/