For 16.0 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:atikon-it:forks/16.0/home:atikon-it:forks.repo
zypper refresh
zypper install apache2-mod_auth_gssapi
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:atikon-it:forks/15.6/home:atikon-it:forks.repo
zypper refresh
zypper install apache2-mod_auth_gssapi
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:atikon-it:forks/15.5/home:atikon-it:forks.repo
zypper refresh
zypper install apache2-mod_auth_gssapi
For 15.3 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:atikon-it:forks/15.3/home:atikon-it:forks.repo
zypper refresh
zypper install apache2-mod_auth_gssapi