* section.c (SEC_LINKER_MARK): Define.
* bfd-in2.h: Rebuild.
* aoutx.h (NAME(aout,final_link)): Mark sections included in the
link.
(aout_link_input_bfd): Don't link unmarked sections.
* cofflink.c (_bfd_coff_final_link): Mark sections included in the
link.
(_bfd_coff_link_input_bfd): Don't link unmarked sections.
* coff-ppc.c (ppc_bfd_coff_final_link): Mark sections included in
the link.
* elflink.h (elf_bfd_final_link): Mark sections included in the
link.
(elf_link_input_bfd): Don't link unmarked sections.
* xcofflink.c (_bfd_xcoff_bfd_final_link): Mark sections included
in the link.
(xcoff_link_input_bfd): Don't link unmarked sections.