vendor/bc: upgrade to version 7.0.2

This update fixes exiting from an interactive bc session with ^D on
FreeBSD and Linux when using editline.

This bug was caused by the macOS fix for editline in version 7.0.0,
which has been reverted in this version.

Reported by: mack@macktronics.com

(cherry picked from commit c2c85f88902d18d2e9702381f1628112e15a5c3c)
(cherry picked from commit 9b04aee86ccd58a6f3c936e0cd95bb9305a69848)