Amend documentation to reflect that `meson install` is not run

[dnicolodi]

Amend the documentation to reflect the fact that we don't actually run meson install but just re-implement it. This affects two Meson features: install_rpath support, and running scripts registered with meson.add_install_script(). Both things have no effect when building a package with meson-python.

[dnicolodi]

Also explicitly list the meson install options recognized by meson-python in https://meson-python.readthedocs.io/en/latest/reference/pyproject-settings.html#cmdoption-arg-tool.meson-python.args.install and https://meson-python.readthedocs.io/en/latest/reference/config-settings.html#cmdoption-arg-install-args or find a way to do not have to repeat the content twice.

Most of the meson install options not handled by meson-python aren't relevant, but it's possible --strip may be or some new option gets added to meson install that we must start handling.

[FFY00]

I ran into this today, where I explicitly needed to perform some artifact fixup that was not possible any other sane way in meson other than using meson.add_install_script().

[dnicolodi]

@FFY00 AFAIK the only feature offered to a script executed as a meson.add_install_script() vs a script executed as a custom_target() is the knowledge of the installation location via environment variables like MESON_INSTALL_PREFIX and MESON_INSTALL_DESTDIR_PREFIX. The installation path is hard to define for packages installed as wheels. Therefore, I am not able to imagine what requirement makes an installation script the right solution. Can you explain your use case in more detail?

[eli-schwartz]

Stuff like auditwheel repair, maybe?

[FFY00]

Stuff like auditwheel repair, maybe?

Yes, exactly. In my particular case, I needed to perform a small edit to the binary format data of certain artifacts.

This is not possible in Meson AFAIK, as you can't pass a build target as the input for a custom target,

[dnicolodi]

The Meson documentation is not very clear on this, but you can pass the object returned by build_target() as input to a custom_target().