❯ make ptl-shared verbose=1
Building CXX object source/externals/ptl/src/CMakeFiles/ptl-shared.dir/TaskGroup.cc.o
Building CXX object source/externals/ptl/src/CMakeFiles/ptl-shared.dir/TaskRunManager.cc.o
Building CXX object source/externals/ptl/src/CMakeFiles/ptl-shared.dir/ThreadData.cc.o
Building CXX object source/externals/ptl/src/CMakeFiles/ptl-shared.dir/ThreadPool.cc.o
Building CXX object source/externals/ptl/src/CMakeFiles/ptl-shared.dir/Threading.cc.o
Building CXX object source/externals/ptl/src/CMakeFiles/ptl-shared.dir/Timer.cc.o
Building CXX object source/externals/ptl/src/CMakeFiles/ptl-shared.dir/UserTaskQueue.cc.o
Building CXX object source/externals/ptl/src/CMakeFiles/ptl-shared.dir/VUserTaskQueue.cc.o
Linking CXX shared library ../../../../BuildProducts/lib/libG4ptl.dylib
Undefined symbols for architecture arm64:
  "std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char>>::str() const", referenced from:
      void PTL::EnvSettings::insert<unsigned long long>(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, unsigned long long) in TaskRunManager.cc.o
      PTL::ThreadPool::initialize_threadpool(unsigned long) in ThreadPool.cc.o
      PTL::ThreadPool::destroy_threadpool() in ThreadPool.cc.o
      void PTL::EnvSettings::insert<bool>(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, bool) in ThreadPool.cc.o
      void PTL::EnvSettings::insert<int>(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, int) in ThreadPool.cc.o
      void PTL::EnvSettings::insert<unsigned long>(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, unsigned long) in ThreadPool.cc.o
      PTL::UserTaskQueue::ExecuteOnAllThreads(PTL::ThreadPool*, std::__1::function<void ()>) in UserTaskQueue.cc.o
      ...
  "std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char>>::str(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&)", referenced from:
      std::__1::basic_istringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>::basic_istringstream[abi:v15006](std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, unsigned int) in TaskRunManager.cc.o
      std::__1::basic_istringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>::basic_istringstream[abi:v15006](std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, unsigned int) in ThreadPool.cc.o
      std::__1::basic_istringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>::basic_istringstream[abi:v15006](std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, unsigned int) in UserTaskQueue.cc.o
  "VTT for std::__1::basic_stringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>", referenced from:
      void PTL::EnvSettings::insert<unsigned long long>(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, unsigned long long) in TaskRunManager.cc.o
      std::__1::basic_stringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>::basic_stringstream[abi:v15006]() in TaskRunManager.cc.o
      std::__1::basic_stringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>::~basic_stringstream() in TaskRunManager.cc.o
      std::__1::basic_stringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>::basic_stringstream[abi:v15006]() in ThreadPool.cc.o
      std::__1::basic_stringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>::~basic_stringstream() in ThreadPool.cc.o
      void PTL::EnvSettings::insert<bool>(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, bool) in ThreadPool.cc.o
      void PTL::EnvSettings::insert<int>(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, int) in ThreadPool.cc.o
      ...
  "VTT for std::__1::basic_istringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>", referenced from:
      unsigned long long PTL::GetEnv<unsigned long long>(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, unsigned long long) in TaskRunManager.cc.o
      std::__1::basic_istringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>::basic_istringstream[abi:v15006](std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, unsigned int) in TaskRunManager.cc.o
      std::__1::basic_istringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>::~basic_istringstream() in TaskRunManager.cc.o
      int PTL::GetEnv<int>(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, int) in ThreadPool.cc.o
      unsigned long PTL::GetEnv<unsigned long>(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, unsigned long) in ThreadPool.cc.o
      std::__1::basic_istringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>::basic_istringstream[abi:v15006](std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, unsigned int) in ThreadPool.cc.o
      std::__1::basic_istringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>::~basic_istringstream() in ThreadPool.cc.o
      ...
  "vtable for std::__1::basic_stringbuf<char, std::__1::char_traits<char>, std::__1::allocator<char>>", referenced from:
      unsigned long long PTL::GetEnv<unsigned long long>(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, unsigned long long) in TaskRunManager.cc.o
      std::__1::basic_istringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>::basic_istringstream[abi:v15006](std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, unsigned int) in TaskRunManager.cc.o
      void PTL::EnvSettings::insert<unsigned long long>(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, unsigned long long) in TaskRunManager.cc.o
      std::__1::basic_istringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>::~basic_istringstream() in TaskRunManager.cc.o
      std::__1::basic_stringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>::basic_stringstream[abi:v15006]() in TaskRunManager.cc.o
      std::__1::basic_stringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>::~basic_stringstream() in TaskRunManager.cc.o
      int PTL::GetEnv<int>(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, int) in ThreadPool.cc.o
      ...
  NOTE: a missing vtable usually means the first non-inline virtual member function has no definition.
  "vtable for std::__1::basic_stringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>", referenced from:
      std::__1::basic_stringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>::basic_stringstream[abi:v15006]() in TaskRunManager.cc.o
      std::__1::basic_stringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>::basic_stringstream[abi:v15006]() in ThreadPool.cc.o
      std::__1::basic_stringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>::basic_stringstream[abi:v15006]() in UserTaskQueue.cc.o
  NOTE: a missing vtable usually means the first non-inline virtual member function has no definition.
  "vtable for std::__1::basic_istringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>", referenced from:
      std::__1::basic_istringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>::basic_istringstream[abi:v15006](std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, unsigned int) in TaskRunManager.cc.o
      std::__1::basic_istringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>::basic_istringstream[abi:v15006](std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, unsigned int) in ThreadPool.cc.o
      std::__1::basic_istringstream<char, std::__1::char_traits<char>, std::__1::allocator<char>>::basic_istringstream[abi:v15006](std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char>> const&, unsigned int) in UserTaskQueue.cc.o
  NOTE: a missing vtable usually means the first non-inline virtual member function has no definition.
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[3]: *** [BuildProducts/lib/libG4ptl.2.3.3.dylib] Error 1
make[2]: *** [source/externals/ptl/src/CMakeFiles/ptl-shared.dir/all] Error 2
make[1]: *** [source/externals/ptl/src/CMakeFiles/ptl-shared.dir/rule] Error 2
make: *** [ptl-shared] Error 2