gdb/

gdb/
	* symfile.c (build_section_addr_info_from_bfd): New.
	(build_section_addr_info_from_objfile): Base it on
	build_section_addr_info_from_bfd.
	(addrs_section_compar, addrs_section_sort): New.
	(addr_info_make_relative): New variables my_cleanup, abfd_addrs,
	addrs_sorted, abfd_addrs_sorted and addrs_to_abfd_addrs.  Build
	addrs_to_abfd_addrs.  Use it for recalculating ADDRS.

gdb/testsuite/
	* gdb.base/dup-sect.exp, gdb.base/dup-sect.S: New.