Ben Gamari authored Mar 23, 2022 and Matthew Pickering committed Jun 16, 2022

Here we introduce proper support for compilation of C++ objects. This
includes:

 * logic in `configure` to detect the C++ toolchain and propagating this
   information into the `settings` file
 * logic in the driver to use the C++ toolchain when compiling C++
   sources

(cherry picked from commit fb579e15)