contrib/bc: update to version 4.0.2

Merge commit '2858419a0ee2b8f5827de72c00618bcd69ebc5fc'

This update fixes the initialization of "scale" to 20 if started with
-l and the initial statement leads to an error (e.g. contains a syntax
error). Scale was initialized to 0 in that case.

Another change is the support of job control in interactive mode with
line editing enabled. The control characters have been interpreted as
editing commands only, prior to this version.

(cherry picked from commit 8c39e25220bb88cd027d0c3b0fe86e52f6abd150)