Extend flags to support multibit and enum bitfields.

Extend flags to support multibit and enum bitfields.

gdb/ChangeLog:

	Extend flags to support multibit and enum bitfields.
	NEWS: Document new features.
	* c-typeprint.c (c_type_print_varspec_prefix): Handle TYPE_CODE_FLAGS.
	(c_type_print_varspec_suffix, c_type_print_base): Ditto.
	* gdbtypes.c (arch_flags_type): Don't assume all fields are one bit.
	(append_flags_type_field): New function.
	(append_flags_type_flag): Call it.
	* gdbtypes.h (append_flags_type_field): Declare.
	* target-descriptions.c (struct tdesc_type_flag): Delete.
	(enum tdesc_type_kind) <TDESC_TYPE_BOOL>: New enum value.
	(enum tdesc_type_kind) <TDESC_TYPE_ENUM>: Ditto.
	(struct tdesc_type) <u.f>: Delete.
	(tdesc_predefined_types): Add "bool".
	(tdesc_predefined_type): New function.
	(tdesc_gdb_type): Handle TDESC_TYPE_BOOL, TDESC_TYPE_ENUM.
	Update TDESC_TYPE_FLAGS support.
	(tdesc_free_type): Handle TDESC_TYPE_ENUM.  Update TDESC_TYPE_FLAGS.
	(tdesc_create_flags): Update.
	(tdesc_create_enum): New function.
	(tdesc_add_field): Initialize start,end to -1.
	(tdesc_add_typed_bitfield): New function.
	(tdesc_add_bitfield): Call it.
	(tdesc_add_flag): Allow TDESC_TYPE_STRUCT.  Update.
	(tdesc_add_enum_value): New function.
	(maint_print_c_tdesc_cmd): Fold TDESC_TYPE_FLAGS support into
	TDESC_TYPE_STRUCT.  Handle TDESC_TYPE_ENUM.
	* target-descriptions.h (tdesc_create_enum): Declare.
	(tdesc_add_typed_bitfield, tdesc_add_enum_value): Declare.
	* valprint.c (generic_val_print_enum_1): New function.
	(generic_val_print_enum): Call it.
	(val_print_type_code_flags): Make static.  Handle multibit bitfields
	and enum bitfields.
	* valprint.h (val_print_type_code_flags): Delete.
	* xml-tdesc.c (struct tdesc_parsing_data) <current_type_is_flags>:
	Delete.  All uses removed.
	(tdesc_start_enum): New function.
	(tdesc_start_field): Handle multibit and enum bitfields.
	(tdesc_start_enum_value): New function.
	(enum_value_attributes, enum_children, enum_attributes): New static
	globals.
	(feature_children): Add "enum".
	* features/gdb-target.dtd (enum, evalue): New elements.

gdb/doc/ChangeLog:

	* gdb.texinfo (Target Descriptions): New menu item "Enum Target Types".
	(Target Description Format): Mention enum types.  Update docs on
	flags types.
	(Predefined Target Types): Add "bool".
	(Enum Target Types): New node.

gdb/testsuite/ChangeLog:

	* gdb.xml/extra-regs.xml: Add enum, mixed_flags values.
	* gdb.xml/tdesc-regs.exp (load_description): New arg xml_file.
	All callers updated.  Add tests for enums, mixed flags register.