root5: Add devel block
root5: Add devel block

Provide devel block for 5.34.34 release. Update options to behave
nicely with new minimal/gminimal behaviour.

xgarrido/homebrew-cadfael,SuperNEMO-DBD/homebrew-cadfael,xgarrido/homebrew-cadfael,SuperNEMO-DBD/homebrew-cadfael