* som.c (struct som_misc_symbol_info): Add is_comdat, is_common and

	* som.c (struct som_misc_symbol_info): Add is_comdat, is_common and
	dup_common fields.
	(setup_sections): Use som_subspace_dictionary_record struct instead
	subspace_dictionary_record.  Set SEC_LINK_ONCE if subspace is
	is_comdat, is_common or dup_common.
	(som_prep_headers): Use som_subspace_dictionary_record struct.  Set
	is_comdat, is_common and dup_common in section subspace_dict from
	copy_data.
	(som_begin_writing): Use som_subspace_dictionary_record struct.
	(som_finish_writing): Likewise.
	(som_bfd_derive_misc_symbol_info): Add support to set is_comdat,
	is_common and dup_common flags in info for symbol.  Add comment
	regarding linker support for these fields.  Slightly reorganize
	function.
	(som_build_and_write_symbol_table): Set is_comdat, is_common and
	dup_common fields in symbol table from symbol info.
	(bfd_som_set_subsection_attributes): Add comdat, common and dup_common
	arguments.  Set corresponding fields in copy_data.  Change all callers.
	(som_bfd_ar_write_symbol_stuff): Set dup_common flag in library
	symbol table.
	(som_vec): Add SEC_LINK_ONCE to applicable section flags.
	* som.h (som_subspace_dictionary_record): Define.
	(som_copyable_section_data_struct): Add is_comdat, is_common and
	dup_common fields.
	(som_section_data_struct): Use som_subspace_dictionary_record struct
	instead of subspace_dictionary_record.
	(bfd_boolean bfd_som_set_subsection_attributes): Adjust prototype.
	* config/obj-som.c (obj_som_init_stab_section): Add new arguments in
	call to obj_set_subsection_attributes.
	(obj_som_init_stab_section): Likewise.
	* config/tc-hppa.c (default_subspace_dict): Add comdat field.
	(pa_def_subspaces): Provide comdat default.
	(pa_subspace): Handle new "comdat" parameter.  Set SEC_LINK_ONCE and
	not SEC_IS_COMMON if section is comdat, common or dup_common.  Update
	calls to create_new_subspace and update_subspace to pass comdat flag.
	(create_new_subspace, update_subspace): Add new comdat argument.  Use
	it in calls to obj_set_subsection_attributes.
	* doc/c-hppa.texi (.subspa, .nsubspa): Document new comdat parameter
	and use of comdat, common and dup_comm parameters.