I failed to note that cibuidwheel copies files into container. And when package references files in parent dirs, they can not be found, because they were not copied. Like this:

[project]
name = "gv"
version = "14.1.0.dev202511292323"  # TODO: dynamic

[tool.setuptools]
py-modules = ["gv"]

[[tool.setuptools.ext-modules]]
name = "gv"
sources = ["gv.i"]
include-dirs = ["../../lib"]

I didn't bang my head against the wall for too long, but it is still painful. Would be nice of cibuildwheel could detect this situation, and provide user with some bandages and pain relievers.