* grub-core/io/xzio.c: New file.
	* grub-core/lib/xzembed/xz.h: New file (from xembed).
	* grub-core/lib/xzembed/xz_config.h: Likewise.
	* grub-core/lib/xzembed/xz_dec_bcj.c: Likewise.
	* grub-core/lib/xzembed/xz_dec_lzma2.c: Likewise.
	* grub-core/lib/xzembed/xz_dec_stream.c: Likewise.
	* grub-core/lib/xzembed/xz_lzma2.h: Likewise.
	* grub-core/lib/xzembed/xz_private.h: Likewise.
	* grub-core/lib/xzembed/xz_stream.h: Likewise.
	* include/grub/file.h (grub_file_filter_id): New compression filter
	GRUB_FILE_FILTER_XZIO.