How to supress prompt on bc 5.3.1

From: Masachika ISHIZUKA <ish_at_amail.plala.or.jp>
Date: Tue, 14 Jun 2022 01:01:41 UTC
  I updated to master-n256084-5dd1f6f1441 (1400061) and this
leads to bc to 5.3.1.
  Previosly, 'BC-ENV-APRG=-P' or 'bc -P' were working but it
doesn't work on 5.3.1.  Is there any way to supress prompt ?
-- 
Masachika ISHIZUKA