bc: Vendor import new version 3.3.3

(cherry picked from commit 028616d0dd69a3da7a30cb94d35f040bf2ced6b9)

Make length(0) and length(0.0) return 1 for compatibility with GNU bc
and the traditional FreeBSD bc.

Fix a potential division by zero error in a non-standard (extended)
math library function.

(cherry picked from commit f165641df4da1752f8bb1f55c1e602cdb657fba4)

Approved by: re