* dwarf2read.c (comp_unit_head): Use unsigned int consistently

	* dwarf2read.c (comp_unit_head): Use unsigned int consistently
	for dwarf section offsets and sizes.
	(dwarf2_cu): Ditto.
	(dwarf2_per_cu_data): Ditto.
	(create_all_comp_units): Change offset to unsigned int.
	(load_full_comp_unit,find_partial_die_in_comp_unit,find_partial_die,
	dwarf2_find_containing_comp_unit,dwarf2_find_comp_unit): Ditto.

	* dwarf2read.c (read_initial_length): Delete cu_header arg.
	All callers updated.
	(read_checked_initial_length_and_offset): New function.
	(read_offset_1): New function.
	(read_offset): Call it.
	(dwarf_decode_line_header): Call read_checked_initial_length_and_offset
	instead of read_initial_length.  Call read_offset_1 instead of
	read_offset.

	* dwarf2read.c (dwarf2_get_ref_die_offset): Remove unused arg `cu'.
	All callers updated.

	* dwarf2read.c (dwarf_attr_name): Unconditionally support all
	DW_AT_MIPS_* except DW_AT_MIPS_fde which collides with
	DW_AT_HP_block_index.