* features/library-list.dtd: Allow "section" elements as children

	* features/library-list.dtd: Allow "section" elements as children
	of "library".  Add "section" element and describe its attributes.

	* solib-target.c (struct lm_info): Add section_bases member.
	(library_list_start_segment): Error out if seen a section element.
	(library_list_start_section): New.
	(library_list_end_library): New.
	(solib_target_free_library_list): Free section_bases.
	(section_attributes): New.
	(library_children): Make "segment" optional.  Add "section" child.
	(library_list_children): Register library_list_end_library.
	(solib_target_relocate_section_addresses): Handle section bases.

	* NEWS: Mention new qXfer:libraries:read section offsets support.

doc/
	* gdb.texinfo (Library List Format): Update to mention the
	possibility to pass section addresses instead of segment
	addresses.