feat: add entrypoint for cmake modules dir

setup.py

@@ -144,6 +144,8 @@ def remove_output(*sources: str) -> Iterator[None]:
             stdout=sys.stdout,
             stderr=sys.stderr,
         )
+        if not global_sdist:
+            Path("pybind11/share/cmake/pybind11/__init__.py").touch()
 
     txt = get_and_replace(setup_py, version=version, extra_cmd=extra_cmd)
     code = compile(txt, setup_py, "exec")

tests/extra_python_package/test_files.py

@@ -166,6 +166,7 @@ def test_build_sdist(monkeypatch, tmpdir):
     files |= {f"pybind11{n}" for n in local_sdist_files}
     files.add("pybind11.egg-info/entry_points.txt")
     files.add("pybind11.egg-info/requires.txt")
+    files.add("pybind11/share/cmake/pybind11/__init__.py")
     assert simpler == files
 
     with open(os.path.join(MAIN_DIR, "tools", "setup_main.py.in"), "rb") as f:
@@ -252,6 +253,7 @@ def tests_build_wheel(monkeypatch, tmpdir):
         "dist-info/entry_points.txt",
         "dist-info/top_level.txt",
     }
+    files.add("pybind11/share/cmake/pybind11/__init__.py")
 
     with zipfile.ZipFile(str(wheel)) as z:
         names = z.namelist()

tools/setup_main.py.in

@@ -38,6 +38,9 @@ setup(
         ],
         "pipx.run": [
              "pybind11 = pybind11.__main__:main",
+        ],
+        "cmake.modules": [
+            "pybind11 = pybind11.share.cmake.pybind11",
         ]
     },
     cmdclass=cmdclass