* symfile.h (struct dwarf2_debug_sections) <macro>: New field.

	* symfile.h (struct dwarf2_debug_sections) <macro>: New field.
	* dwarf2read.c (read_indirect_string_at_offset): New function.
	(read_indirect_string): Use it.
	(dwarf_decode_macro_bytes): New function, taken from
	dwarf_decode_macros.  Handle DW_MACRO_GNU_*.
	(dwarf_decode_macros): Use it.  handle DW_MACRO_GNU_*.
	(dwarf_parse_macro_header, skip_form_bytes, skip_unknown_opcode):
	New functions.
	(struct dwarf2_per_objfile) <macro>: New field.
	(dwarf2_elf_names): Add .debug_macro.
	(dwarf2_macros_too_long_complaint): Add 'section' argument.
	(dwarf2_locate_sections): Handle new section.
	(read_file_scope): Handle DW_AT_GNU_macros.
	(dwarf2_per_objfile_free): Unmap the .debug_macro section.