I was trying to fix this package for Leap 15.4 (and failing), but while at it I was wondering why you need the BuildRequire pkgconfig(guile-3.0) (which makes the build unresolvable for Leap, SLE, etc.), if you then disable it when building (-Dguile=disabled). I think that leaving this out would be a first step towards fixing this for Leap (then we have other problems like minimum g++ > 8 and readline not being found when building it locally for whatever reason...).