build: add build-backend option
build: add build-backend option

Allows the user to specify the build backend to use.

The xcode backend is not supported as it fails to build the project and
has too many issues, for example:

- https://github.com/mesonbuild/meson/issues/8552
- https://github.com/mesonbuild/meson/issues/8270
- https://github.com/mesonbuild/meson/issues/8243

gopro/gopro-lib-node.gl,gopro/gopro-lib-node.gl,gopro/gopro-lib-node.gl,gopro/gopro-lib-node.gl