add indirect_symbol to mach-o port.

add indirect_symbol to mach-o port.

bfd:

	* mach-o.c (bfd_mach_o_count_indirect_symbols): New.
	(bfd_mach_o_build_dysymtab_command): Populate indirect symbol table.
	* mach-o.h (bfd_mach_o_asymbol): Move declaration to start of the
	file. (bfd_mach_o_section): Add indirect_syms field.

gas:

	* config/obj-macho.c (obj_mach_o_set_symbol_qualifier): Switch off
	lazy when the symbol is private_extern.
	(obj_mach_o_indirect_sym): New type.
	(obj_mach_o_indirect_symbol): New.
	(mach_o_pseudo_table): Use obj_mach_o_indirect_symbol.
	(obj_macho_frob_label): Adjust to avoid adding bsyms for locals.
	(obj_macho_frob_label): Likewise.  Adjust external and comm
	symbol tests.
	(obj_mach_o_set_indirect_symbols): New.
	(obj_mach_o_frob_file_after_relocs): New.
	*config/obj-macho.h (obj_frob_file_after_relocs): Define.
	(obj_mach_o_frob_file_after_relocs): Declare.

include/mach-o:

	* loader.h (BFD_MACH_O_INDIRECT_SYM_LOCAL): New.
	(BFD_MACH_O_INDIRECT_SYM_ABS): New

gas/testsuite:

	* gas/mach-o/dysymtab-2.d: New.
	* gas/mach-o/err-syms-4.s: New.
	* gas/mach-o/err-syms-5.s: New.
	* gas/mach-o/err-syms-6.s: New.
	* gas/mach-o/symbols-6-64.d: New.
	* gas/mach-o/symbols-6-64.s: New.
	* gas/mach-o/symbols-6.d: New.
	* gas/mach-o/symbols-6.s: New.