ci: build cp12-abi3 wheels, and run abi3audit on them

CMakeLists.txt

@@ -5,7 +5,6 @@ find_package(Python 3.8 COMPONENTS Interpreter Development.Module REQUIRED)
 find_package(nanobind CONFIG REQUIRED)
 find_package(OpenMP)
 
-# TODO: stable ABI?
 nanobind_add_module(cpu_helpers src/nifty_ls/cpu_helpers.cpp NOMINSIZE)
 
 target_compile_options(cpu_helpers PRIVATE

pyproject.toml

@@ -28,6 +28,7 @@ metadata.version.provider = "scikit_build_core.metadata.setuptools_scm"
 minimum-version = "0.8"
 build-dir = "build/{wheel_tag}"
 # editable.rebuild = true  # use with --no-build-isolation
+wheel.py-api = "cp312"
 
 # For debugging:
 # cmake.build-type = "Debug"
@@ -54,3 +55,10 @@ archs = "auto64"
 test-command = "pytest --benchmark-skip {project}/tests"
 test-extras = "test"
 skip = "pp* *-musllinux_*"
+
+[tool.cibuildwheel.linux]
+repair-wheel-command = [
+  "auditwheel repair -w {dest_dir} {wheel}",
+  # run abi3audit on wheels tagged with abi3
+  'case "$(basename {wheel})" in *"-abi3-"*) pipx run abi3audit --strict --report {wheel};; esac',
+]