Recognize the new ELF compression type for ZSTD.

There is more work to be done to actually support compression and
decompression using the zstd library, but I will leave that to the
champions of the new compression option.

binutils/
	* binutils/readelf.c (process_section_headers): Add support for
	ELFCOMPRESS_ZSTD.

binutils/readelf.c

@@ -7710,6 +7710,8 @@ process_section_headers (Filedata * filedata)
 		    {
 		      if (chdr.ch_type == ELFCOMPRESS_ZLIB)
 			printf ("       ZLIB, ");
+		      else if (chdr.ch_type == ELFCOMPRESS_ZSTD)
+			printf ("       ZSTD, ");
 		      else
 			printf (_("       [<unknown>: 0x%x], "),
 				chdr.ch_type);