Update meson to version 1.6.1 / rev 120 via SR 1238473
https://build.opensuse.org/request/show/1238473
by user dimstar + dimstar_suse
- Drop the bcond on setuptools, its primary flavor will live in Ring 0.
- Drop patch meson-distutils.patch, not required.
- Instruct autosetup macro to apply all patches.