vendor/bc: upgrade to version 7.0.1

This update fixes building bc on FreeBSD with non-default compilers
(GCC-12, GCC-13). GCC warned about casting argv from non-const to const
and since warnings are treated as errors, the build failed.

(cherry picked from commit 1e19146fc7692f59e8dfc5da7957e938cd0b81b8)