Automatically call CMake as part of PEP 517 build

MANIFEST.in

@@ -0,0 +1,3 @@
+include CMakeLists.txt
+graft csrc
+graft include

pyproject.toml

@@ -1,6 +1,6 @@
 [build-system]
-requires = ["setuptools >= 63.0.0"]
-build-backend = "setuptools.build_meta"
+requires = ["scikit-build-core", "setuptools >= 63.0.0"]
+build-backend = "scikit_build_core.setuptools.build_meta"
 
 [project]
 name = "bitsandbytes"

setup.py

@@ -2,7 +2,11 @@
 #
 # This source code is licensed under the MIT license found in the
 # LICENSE file in the root directory of this source tree.
+from distutils.errors import DistutilsModuleError
+from warnings import warn
+
 from setuptools import find_packages, setup
+from setuptools.command.build_py import build_py
 from setuptools.dist import Distribution
 
 
@@ -12,4 +16,26 @@ def has_ext_modules(self):
         return True
 
 
-setup(version="0.47.0.dev0", packages=find_packages(), distclass=BinaryDistribution)
+class ExtBuildPy(build_py):
+    def run(self):
+        # build_cmake needs to be called prior to build_py, as the latter
+        # collects the files output into the package directory.
+        try:
+            self.run_command("build_cmake")
+        except DistutilsModuleError:
+            warn(
+                "scikit-build-core not installed, CMake will not be invoked automatically. "
+                "Please install scikit-build-core or run CMake manually to build extensions."
+            )
+        super().run()
+
+
+setup(
+    version="0.47.0.dev0",
+    packages=find_packages(),
+    distclass=BinaryDistribution,
+    cmake_source_dir=".",
+    cmdclass={
+        "build_py": ExtBuildPy,
+    },
+)