rubygem-ffi-compiler from home:crameleon:LibertaCasa:Mastodon project
Select Your Operating System
Add repository and install manually
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:crameleon:LibertaCasa:Mastodon/15.4/home:crameleon:LibertaCasa:Mastodon.repo zypper refresh zypper install rubygem-ffi-compiler