Vdirsyncer calling gcc?

dzu@krikkit:~$ strace -f -o/tmp/strace vdirsyncer sync dzu_calendar/detlev-arbeit
Syncing dzu_calendar/detlev-arbeit
dzu@krikkit:~$ grep 'execve("/usr/bin/gcc' /tmp/strace
278133 execve("/usr/bin/gcc", ["/usr/bin/gcc", "-Wl,-t", "-o", "/tmp/tmpwum14m08", "-lSecurity"], 0x7f7d6bd84ff0 /* 54 vars */ <unfinished ...>
278138 execve("/usr/bin/gcc", ["/usr/bin/gcc", "-Wl,-t", "-o", "/tmp/tmpbpaorirx", "-lCoreServices"], 0x7f7d6bd85370 /* 54 vars */ <unfinished ...>
278143 execve("/usr/bin/gcc", ["/usr/bin/gcc", "-Wl,-t", "-o", "/tmp/tmp9ytbim7o", "-lFoundation"], 0x7f7d6bd85370 /* 54 vars */ <unfinished ...>
dzu@krikkit:~$ 

dzu@krikkit:$ cd /usr/lib/python3.10/
dzu@krikkit:/usr/lib/python3.10$ grep -ar c_compiler .
./ctypes/__pycache__/util.cpython-310.pyc:c_compilertempargsrLproctraceresfilerrr
                                                                                 _findLib_gccfs`
./ctypes/util.py:        c_compiler = shutil.which('gcc')
./ctypes/util.py:        if not c_compiler:
./ctypes/util.py:            c_compiler = shutil.which('cc')
./ctypes/util.py:        if not c_compiler:
./ctypes/util.py:            args = [c_compiler, '-Wl,-t', '-o', temp.name, '-l' + name]
dzu@krikkit:/usr/lib/python3.10$ 

#!/usr/bin/python

import ctypes
from ctypes.util import find_library

find_library("Security")

dzu@krikkit:~$ strace -f -o /tmp/strace ~/src/python/find_library.py 
dzu@krikkit:~$ grep 'execve("/usr/bin/gcc' /tmp/strace
282420 execve("/usr/bin/gcc", ["/usr/bin/gcc", "-Wl,-t", "-o", "/tmp/tmpbqeliwxa", "-lSecurity"], 0x7faedfcdfc50 /* 50 vars */ <unfinished ...>
dzu@krikkit:~$ 

zu@krikkit:/usr/lib/python3/dist-packages$ grep -r "find_library('CoreServices"
keyring/backends/macOS/api.py:_core = ctypes.CDLL(find_library('CoreServices'))
dzu@krikkit:/usr/lib/python3/dist-packages$ 

dzu@krikkit:~$ apt-cache rdepends python3-send2trash 
python3-send2trash
Reverse Depends:
  dupeguru
  thonny
  organize
  python3-jupyter-server
  python3-notebook
  eric
  displaycal
dzu@krikkit:~$ for w in $(apt-cache rdepends python3-send2trash | tail +3); do dpkg -l $w ; done
dpkg-query: no packages found matching dupeguru
dpkg-query: no packages found matching thonny
dpkg-query: no packages found matching organize
dpkg-query: no packages found matching python3-jupyter-server
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name             Version      Architecture Description
+++-================-============-============-=======================================
ii  python3-notebook 6.4.12-2.1   all          Jupyter interactive notebook (Python 3)
dpkg-query: no packages found matching eric
dpkg-query: no packages found matching displaycal
dzu@krikkit:~$ 

dzu@krikkit:~/.local/lib/python3.10/site-packages$ grep -r "find_library('CoreServ" .
./keyring/backends/macOS/api.py:_core = ctypes.CDLL(find_library('CoreServices'))
dzu@krikkit:~/.local/lib/python3.10/site-packages$ grep -r "find_library('Securit" .
./keyring/backends/macOS/api.py:_sec = ctypes.CDLL(find_library('Security'))
dzu@krikkit:~/.local/lib/python3.10/site-packages$ grep -r "find_library('Foundation" .
./keyring/backends/macOS/api.py:_found = ctypes.CDLL(find_library('Foundation'))
dzu@krikkit:~/.local/lib/python3.10/site-packages$