As we no longer use function pointers for read in common archiving code
archive_xread can be replaced with bb_full_read, and archive_copy_file
with bb_copyfd*
bb_copyfd is split into two functions bb_copyfd_size and bb_copyfd_eof,
they share a common backend.
diff --git a/archival/libunarchive/archive_xread_all.c b/archival/libunarchive/archive_xread_all.c
index cfe046b..ba9ade2 100644
--- a/archival/libunarchive/archive_xread_all.c
+++ b/archival/libunarchive/archive_xread_all.c
@@ -24,7 +24,7 @@
 {
 	ssize_t size;
 
-	size = archive_xread(archive_handle, buf, count);
+	size = bb_full_read(archive_handle->src_fd, buf, count);
 	if (size != count) {
 		bb_error_msg_and_die("Short read");
 	}