Promote newer compressors to the start of the list.

compat.c

@@ -88,16 +88,14 @@ int filesfrom_convert = 0;
 
 struct name_num_obj valid_compressions = {
 	"compress", NULL, NULL, 0, 0, {
-		{ CPRES_ZLIBX, "zlibx", NULL },
-		{ CPRES_ZLIB, "zlib", NULL },
 #ifdef SUPPORT_ZSTD
-		/* TODO decide where in the default preference order this should go. */
 		{ CPRES_ZSTD, "zstd", NULL },
 #endif
 #ifdef SUPPORT_LZ4
-		/* TODO decide where in the default preference order this should go. */
 		{ CPRES_LZ4, "lz4", NULL },
 #endif
+		{ CPRES_ZLIBX, "zlibx", NULL },
+		{ CPRES_ZLIB, "zlib", NULL },
 		{ CPRES_NONE, "none", NULL },
 		{ 0, NULL, NULL }
 	}