⚙️ Add ability to build from Dockerfiles directly

vendor/github.com/asottile/dockerfile/setup.py

@@ -0,0 +1,37 @@
+import os.path
+import platform
+import sys
+
+from setuptools import Extension
+from setuptools import setup
+
+if not os.path.exists('vendor/github.com/moby/buildkit/frontend'):
+    print('moby checkout is missing!')
+    print('Run `git submodule update --init`')
+    exit(1)
+
+if sys.platform != 'win32' and platform.python_implementation() == 'CPython':
+    try:
+        import wheel.bdist_wheel
+    except ImportError:
+        cmdclass = {}
+    else:
+        class bdist_wheel(wheel.bdist_wheel.bdist_wheel):
+            def finalize_options(self) -> None:
+                self.py_limited_api = f'cp3{sys.version_info[1]}'
+                super().finalize_options()
+
+        cmdclass = {'bdist_wheel': bdist_wheel}
+else:
+    cmdclass = {}
+
+setup(
+    ext_modules=[
+        Extension(
+            'dockerfile', ['pylib/main.go'],
+            py_limited_api=True, define_macros=[('Py_LIMITED_API', None)],
+        ),
+    ],
+    cmdclass=cmdclass,
+    build_golang={'root': 'github.com/asottile/dockerfile'},
+)