All machinery works as on ELF, except for automatic loading of ELF
string and symbol tables in the BFD-style open machinery.
* Makefile.def (dependencies): configure-libctf depends on all-bfd
and all its deps.
* Makefile.in: Regenerated.
libctf/
* configure.in: Check for bfd_section_from_elf_index.
* configure: Regenerate.
* config.h.in [HAVE_BFD_ELF]: Likewise.
* libctf/ctf_open_bfd (ctf_bfdopen_ctfsect): Use it.
abfd is potentially unused now.