PR symtab/16426

	* dwarf2read.c (dwarf2_get_dwz_file): Call gdb_bfd_record_inclusion.
	(try_open_dwop_file): Ditto.
	* gdb_bfd.c: #include "vec.h".
	(bfdp): New typedef.
	(struct gdb_bfd_data): New member included_bfds.
	(gdb_bfd_unref): Unref all included bfds.
	(gdb_bfd_record_inclusion): New function.
	* gdb_bfd.h (gdb_bfd_record_inclusion): Declare.
Automatic date update in version.in