Force root/root as names for uid0/gid0 instead of using the system
names. This helps make packed download tarballs more reproducible

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/src/create.c
+++ b/src/create.c
@@ -543,17 +543,8 @@ write_gnu_long_link (struct tar_stat_inf
   union block *header;
 
   header = start_private_header ("././@LongLink", size, 0);
-  if (! numeric_owner_option)
-    {
-      static char *uname, *gname;
-      if (!uname)
-	{
-	  uid_to_uname (0, &uname);
-	  gid_to_gname (0, &gname);
-	}
-      UNAME_TO_CHARS (uname, header->header.uname);
-      GNAME_TO_CHARS (gname, header->header.gname);
-    }
+  UNAME_TO_CHARS ("root", header->header.uname);
+  GNAME_TO_CHARS ("root", header->header.gname);
 
   strcpy (header->buffer + offsetof (struct posix_header, magic),
 	  OLDGNU_MAGIC);