branches/zip: os_file_pwrite(): Make the code compile in InnoDB Hot Backup

when the pwrite system call is not available.

os/os0file.c

@@ -2168,16 +2168,20 @@ os_file_pwrite(
 #else
 	{
 		off_t	ret_offset;
+# ifndef UNIV_HOTBACKUP
 		ulint	i;
+# endif /* !UNIV_HOTBACKUP */
 
 		os_mutex_enter(os_file_count_mutex);
 		os_n_pending_writes++;
 		os_mutex_exit(os_file_count_mutex);
 
+# ifndef UNIV_HOTBACKUP
 		/* Protect the seek / write operation with a mutex */
 		i = ((ulint) file) % OS_FILE_N_SEEK_MUTEXES;
 
 		os_mutex_enter(os_file_seek_mutexes[i]);
+# endif /* UNIV_HOTBACKUP */
 
 		ret_offset = lseek(file, offs, SEEK_SET);
 
@@ -2203,7 +2207,9 @@ os_file_pwrite(
 # endif /* UNIV_DO_FLUSH */
 
 func_exit:
+# ifndef UNIV_HOTBACKUP
 		os_mutex_exit(os_file_seek_mutexes[i]);
+# endif /* !UNIV_HOTBACKUP */
 
 		os_mutex_enter(os_file_count_mutex);
 		os_n_pending_writes--;