* dwarf2-frame.c (decode_frame_entry_1): Handle CIE version 4.

	* dwarf2-frame.c (decode_frame_entry_1): Handle CIE version 4.
	(struct dwarf2_cie) <segment_size>: New field.
	* dwarf2read.c (partial_read_comp_unit_head): Accept DWARF 4.
	(skip_one_die): Handle DW_FORM_flag_present, DW_FORM_sec_offset,
	DW_FORM_exprloc.
	(read_attribute_value): Handle DW_FORM_flag_present,
	DW_FORM_sec_offset, DW_FORM_exprloc.
	(dump_die_shallow): Likewise.
	(attr_form_is_section_offset): Handle DW_FORM_sec_offset.
	(dwarf2_const_value): Handle DW_FORM_exprloc.
	(attr_form_is_block): Likewise.
	(struct line_header) <maximum_ops_per_instruction>: New field.
	(dwarf_decode_line_header): Set new field.
	(dwarf_decode_lines): Handle new field.