* objdump.c: Include sys/mman.h

* objdump.c: Include sys/mman.h
  (print_file_list): Remove f, add map, mapsize, linemap, maxline, last_line, first fields.
  (slurp_file): Add.
  (index_file): Add.
  (print_file_open): Call slurp_file and index_file. Initialize new fields.
  (skip_to_line): Rename to print_line and write only single line.
  (dump_line): Add.
  (show_line): Change to new algorithm.