Don't include libbfd.h outside of bfd, part 3

Fix od-macho.c to use a leb128 function from binutils/dwarf.c rather
than one from bfd/libbfd.c.

binutils/
	* elfcomm.h (HOST_WIDEST_INT): Move to..
	* sysdep.h: ..here.
	* od-macho.c: Don't include libbfd.h.  Do include dwarf.h
	(dump_dyld_info_rebase): Use read_leb128 rather than
	read_unsigned_leb128.
	(dump_dyld_info_bind, dump_dyld_info_export_1): Likewise.
	(dump_segment_split_info): Likewise.
	(dump_dyld_info): Rename vars to avoid shadowing dwarf.h enums.
	(dump_load_command): Likewise.