Bug#1093906: rust-cxx-build: please update to v1.0.122

[Chris Hofstaedtler]

Source: rust-cxx-build
Version: 1.0.87

I'd like to use Debian crates to build pdns and pdns-recursor, but
they need cxx-build (and cxx) 1.0.122. Please update cxx-build (and
cxx).

Thanks,
Chris