First, install the RPM tools:
sudo zypper --non-interactive in --replacefiles --force-resolution rpmlint sshpass rpm-build rpmdevtools wget
Then get the spec file:
wget 'https://github.com/golf-lang/golf/blob/main/golf.spec?raw=true' -O golf.spec
Create RPM build tree:
rpmdev-setuptree
Fetch the Golf source code:
rpmdev-spectool -g -R golf.spec
Install dependencies (zypper doesn't have the tool for this like apt or dnf, so we just parse golf.spec, which is the next best thing):
sudo zypper -n install --replacefiles --force-resolution $(rpmspec --parse golf.spec | grep BuildRequires|sed 's/^.*:\(.*\)$/\1/g')
Build the package:
rpmbuild -ba golf.spec
In the home directory, this will produce file ~/rpmbuild/RPMS/x86_64/golf-<version>-1.x86_64.rpm, where <version> is the Golf's current version, and you can now copy that file to another system with the same Linux installed, and install Golf with (ignore the fact that we didn't sign the package):
sudo zypper install ./golf-<version>-1.x86_64.rpm