For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/games:tools/openSUSE_Tumbleweed/games:tools.repo
zypper refresh
zypper install giflib
For openSUSE Slowroll run the following as root:
zypper addrepo https://download.opensuse.org/repositories/games:tools/openSUSE_Slowroll/games:tools.repo
zypper refresh
zypper install giflib
For 16.0 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/games:tools/16.0/games:tools.repo
zypper refresh
zypper install giflib
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/games:tools/15.6/games:tools.repo
zypper refresh
zypper install giflib