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.

archival/libunarchive/data_extract_to_stdout.c

@@ -18,5 +18,5 @@
 
 extern void data_extract_to_stdout(archive_handle_t *archive_handle)
 {
-	archive_copy_file(archive_handle, fileno(stdout));
+	bb_copyfd_eof(archive_handle->src_fd, fileno(stdout));
 }