MarsSeed [1] filed a deletion request for retroarch-rbp [2]: Long abandoned. Also broken, not compatible with Arch Linux (x86_64).
ArchLinuxARM.org repos carry a retroarch that is compatible with the Raspberry Pi. [1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/retroarch-rbp/
