dict_load_foreigns(): Enclose in #ifndef UNIV_HOTBACKUP.

fil_extend_tablespaces_to_stored_len(): Pass zip_size to fil_read().

buf_page_init_for_backup_restore(): Add parameter zip_size.
Enclose the declaration in buf0buf.h in #ifdef UNIV_HOTBACKUP.

recv_apply_log_recs_for_backup(): Replace the local variable "page"
with the local variable "block".  Add local variable zip_size.