create py.typed for python module (PEP 561)

.gitignore

@@ -58,6 +58,9 @@ src/klayout.pro.user
 build/
 dist/
 
+# python type hints
+py.typed
+
 # IDEs
 .vscode
 

MANIFEST.in

@@ -19,3 +19,4 @@ include src/plugins/*/db_plugin/*.h
 include src/plugins/*/*/db_plugin/*.h
 recursive-include src/plugins/common *.h
 include version.sh
+include src/py.typed

setup.py

@@ -57,6 +57,7 @@ and won't find them. So we need to take away the path with
 from typing import List
 from setuptools import setup, Distribution, find_packages
 from setuptools.extension import Extension, Library
+from pathlib import Path
 import glob
 import os
 import re
@@ -904,6 +905,7 @@ lay = Extension(config.root + '.laycore',
 # Core setup function
 
 if __name__ == "__main__":
+    (Path(__file__).parent / "src/py.typed").touch()
     setup(
         name=config.root,
         version=config.version(),