PR ld/3191

	PR ld/3191
	* dwarf2.c (struct adjusted_section): Renamed from struct
	loadable_section.
	(struct dwarf2_debug): Adjust for renaming.  Add version field.
	(read_attribute_value): Correctly handle DW_FORM_ref_addr for
	DWARF3.
	(find_abstract_instance_name): Pass a pointer to
	attribute instead of offset.  For DW_FORM_ref_addr, get the
	entry at the offset from the .debug_info section.
	(scan_unit_for_symbols): Update.
	(parse_comp_unit): Allow DWARF3.  Save the version.
	(unset_sections): Update for renaming.
	(place_sections): Likewise.  Set new VMAs for DWARF sections
	also.