Add support for generating DWARF-5 format directory and file name tables from the assembler.

PR 25611
	PR 25614
	* dwarf.h (DWARF2_Internal_LineInfo): Add li_address_size and
	li_segment_size fields.
	* dwarf.c (read_debug_line_header): Record the address size and
	segment selector size values (if present) in the lineinfo
	structure.
	(display_formatted_table): Warn if the format count is empty but
	the table itself is not empty.
	Display the format count and entry count at the start of the table
	dump.
	(display_debug_lines_raw): Display the address size and segement
	selector size fields, if present.
	* testsuite/binutils-all/dw5.W: Update expected output.

gas	* dwarf2dbg.c (DWARF2_FILE_TIME_NAME): Default to -1.
	(DWARF2_FILE_SIZE_NAME): Default to -1.
	(DWARF2_LINE_VERSION): Default to the current dwarf level or 3,
	whichever is higher.
	(DWARF2_LINE_MAX_OPS_PER_INSN): Provide a default value of 1.
	(NUM_MD5_BYTES): Define.
	(struct file entry): Add md5 field.
	(get_filenum): Delete and replace with...
	(get_basename): New function.
	(get_directory_table_entry): New function.
	(allocate_filenum): New function.
	(allocate_filename_to_slot): New function.
	(dwarf2_where): Use new functions.
	(dwarf2_directive_filename): Add support for extended .file
	pseudo-op.
	(dwarf2_directive_loc): Allow the use of file number zero with
	DWARF 5 or higher.
	(out_file_list): Rename to...
	(out_dir_and_file_list): Add DWARF 5 support.
	(out_debug_line): Emit extra values into the section header for
	DWARF 5.
	(out_debug_str): Allow for file 0 to be used with DWARF 5.
	* doc/as.texi (.file): Update the description of this pseudo-op.
	* testsuite/gas/elf-dwarf-5-file0.s: Add more lines.
	* testsuite/gas/elf-dwarf-5-file0.d: Update expected dump output.
	* testsuite/gas/lns/lns-diag-1.l: Update expected error message.
	* NEWS: Mention the new feature.

binutils/dwarf.h

@@ -29,6 +29,8 @@ typedef struct
 {
   dwarf_vma	 li_length;
   unsigned short li_version;
+  unsigned char  li_address_size;
+  unsigned char  li_segment_size;
   dwarf_vma      li_prologue_length;
   unsigned char  li_min_insn_length;
   unsigned char  li_max_ops_per_insn;