ZF/Inductive.thy,.ML: renamed from "inductive" to allow re-building without
the keyword "inductive" making the theory file fail
ZF/Makefile: now has Inductive.thy,.ML
ZF/Datatype,Finite,Zorn: depend upon Inductive
ZF/intr_elim: now checks that the inductive name does not clash with
existing theory names
ZF/ind_section: deleted things replicated in Pure/section_utils.ML
ZF/ROOT: now loads Pure/section_utils
(*Dummy theory to document dependencies *)
pair = "upair"