* configure.in: Added new option --with[out]-mmap. Set USE_MMAP if it is given

* configure.in: Added new option --with[out]-mmap.  Set USE_MMAP if it is given
and mmep is available.
* acconfig.h: Undef USE_MMAP.
* configure, config.in: Regenerated.
* aoutx.h: If USE_MMAP is not defined, do all symbol and string table handling
the old way.
(aout_get_external_symbols): Don't complain if last byte of string table is
nonzero.
* libbfd.c [HAVE_MADVISE]: Include sys/types.h and sys/mman.h.
(bfd_free_window) [! USE_MMAP]: Don't define.
(bfd_get_file_window, _bfd_generic_get_section_contents_in_window)
 [! USE_MMAP]: Abort.