An MVP example of consuming Boost via Meson subprojects

Tested to work on:

• Linux with GCC
• Windows with MSVC
• macOS with Clang

To build:

• start a VS dev shell (if on Windows)
• cd into source root
• meson build
• ninja -C build
• build/boosttest

Caveats

• Source code is checkouts of trunk at the time I did this, not any particular release.

• Could be implemented without Wrap files, but they are used here to show the full work flow.

• Libraries with code bits are not built, only headers are exposed.