when compiling with `-DPREFER_SYSTEM_PYBIND11=on` the compilation fails

[muezabdalla]

when trying to compile with -DPREFER_SYSTEM_PYBIND11=on the compilation give this error:

-- Found Python3: /usr/bin/python3.13 (found version "3.13.5") found components: Interpreter Development.Embed
-- Found Python3: /usr/bin/python3.13 (found version "3.13.5") found components: Interpreter
CMake Warning at cmake/generate_version_file.cmake:27 (MESSAGE):
  Could not determine git-version from source code - assuming 6.2.0-0
Call Stack (most recent call first):
  CMakeLists.txt:158 (include)


-- Found TCL: /usr/lib/libtcl8.6.so (Required is at least version "8.5")
-- Found TCL: /usr/lib/libtcl8.6.so
CMake Error at CMakeLists.txt:323 (add_subdirectory):
  add_subdirectory given source "external_dependencies/pybind11" which is not
  an existing directory.


-- OpenCasCade include dirs: /usr/include/opencascade
-- GNU C++ ABI version: 17
CMake Error at libsrc/core/CMakeLists.txt:105 (pybind11_add_module):
  Unknown CMake command "pybind11_add_module".


-- Configuring incomplete, errors occurred!
make[2]: *** [CMakeFiles/netgen.dir/build.make:104: dependencies/src/netgen-stamp/netgen-configure] Error 1
make[1]: *** [CMakeFiles/Makefile2:89: CMakeFiles/netgen.dir/all] Error 2
make: *** [Makefile:136: all] Error 2

I am using netgen-6.2.2505 and python3-pybind11-2.13.6_2