and dwarf_add_AT_with_ref_sig8() to libdwarf producer function list.
Documented the new functions in libdwarf2p.1.mm.
If we already have a DW_AT_sibling attribute we take care not
to add a second one.
dwarfgen now supports some 'class reference' forms (local references
and sig8 references, not yet global references).
Fixed dealloc for dwarf_get_pubtypes to avoid duplicate free.
are really misnamed. Now libdwarf2.1.mm exposes the real meaning
and libdwarf2.1.mm (in commentary) does too.
dwarfgen has fixes so it builds 64bit.
Omissions in dwarfgen which were not processing FORMs right
are corrected.
