build: pyudmaio through CMake for better editor/IDE support

To comfortably edit the C++ part of the binding w/o the lsp raising a
red wall of errors, we need to include it in the compile_commands.json

.gitmodules

@@ -1,3 +1,6 @@
 [submodule "doxygen-awesome-css"]
 	path = doxygen-awesome-css
 	url = https://github.com/jothepro/doxygen-awesome-css.git
+[submodule "pyudmaio/pybind11"]
+	path = pyudmaio/pybind11
+	url = git@github.com:pybind/pybind11.git

CMakeLists.txt

@@ -104,6 +104,19 @@ if(BUILD_TESTING)
     endforeach()
 endif()
 
+# The python binding is usually installed via setuptools;
+# we include the C++ part of it here only to populate the compile-command.json for editors/IDEs
+if(EXISTS "${CMAKE_CURRENT_LIST_DIR}/pyudmaio/pybind11/CMakeLists.txt")
+    message("pybind11 submodule found, adding pyudmaio target")
+    add_subdirectory("${CMAKE_CURRENT_LIST_DIR}/pyudmaio/pybind11")
+    pybind11_add_module(pyudmaio EXCLUDE_FROM_ALL
+        "${CMAKE_CURRENT_LIST_DIR}/pyudmaio/src/PythonBinding.cpp"
+        "${CMAKE_CURRENT_LIST_DIR}/pyudmaio/src/DataHandlerPython.cpp"
+    )
+else()
+    message("skipping python binding, clone pybind11 submodule to include it")
+endif()
+
 # Create debian package containing library
 set(CPACK_GENERATOR "DEB")
 set(CPACK_DEBIAN_PACKAGE_MAINTAINER "Patrick Huesmann <patrick.huesmann@desy.de>")