* dwarf2out.c (dwarf_AT): Handle DW_AT_dwo_name.
(use_debug_types): Adjust comment for DWARF5 DW_UT_type units.
(new_die): Handle DW_TAG_skeleton_unit like DW_TAG_compile_unit.
(is_cu_die, is_unit_die): Likewise.
(should_move_die_to_comdat, break_out_comdat_types): Adjust
comments for DWARF5 DW_UT_type units.
(output_compilation_unit_header): Add UT argument, output
start of DWARF5 .debug_info section header.
(output_comp_unit): Add dwo_id argument. Adjust
output_compilation_unit_header caller, for DW_UT_split_compile
emit dwo_id field, otherwise padding1. Emit padding2 field.
(add_top_level_skeleton_die_attrs): Add DW_AT_dwo_name
rather than DW_AT_GNU_dwo_name attr for -gdwarf-5.
(output_skeleton_debug_sections): Add dwo_id argument, for
-gdwarf-5 emit DWARF 5 DW_UT_skeleton header.
(output_comdat_type_unit): For -gdwarf-5 emit .debug_info
DW_UT_type or DW_UT_split_type units rather than .debug_types.
(dwarf2out_finish): Use DW_TAG_skeleton_unit rather than
DW_TAG_compile_unit for skeleton unit die. Don't add
DW_AT_GNU_dwo_id attributes for -gdwarf-5, instead pass checksum
address to output_comp_unit and output_skeleton_debug_sections.
From-SVN: r241724
