devel/glib20: remove runtime dep on perl5
Since glib-mkenums was rewritten in python in glib 2.53.5, glib20 seems
to no longer need perl5 at runtime. This makes perl5 a build dep only.
Removing the run dep causes some other ports to fail, so add the build
dep to those where needed.
PR: 233138
Approved by: gnome (kwm, maintainer, older version of patch)
Exp-run by: antoine