* xcofflink.c: Extensive changes to support linking shared objects

	* xcofflink.c: Extensive changes to support linking shared objects
	and generating a .loader section.
	* libcoff-in.h (struct xcoff_tdata): Add import_file_id field.
	(struct xcoff_section_tdata): Add first_symndx, last_symndx,
	and ldrel_count fields.
	* libcoff.h: Rebuild.
	* coff-rs6000.c (xcoff_howto_table): Correct reloc names.
	* coffcode.h (styp_to_sec_flags): Don't set any flags if STYP_PAD
	is set.
	* bfd-in.h (bfd_xcoff_import_symbol): Declare.
	(bfd_xcoff_export_symbol): Declare.
	(bfd_xcoff_size_dynamic_sections): Declare.
	* bfd-in2.h: Rebuild.