build failure affecting port: "error: reference to 'filesystem' is ambiguous"

Hello all,

I'm lost on build failure of audio/amsynth (updated to version 1.13.3) on
recent main.
Thre strange thing is if I use llvm from ports, USES+=llvm, it fails with
same error so I suspect that something related to main.

Any help is welcome and I didn't openned an upstream PR yet.

Thanks,

---
src/Configuration.cpp:35:20: error: reference to 'filesystem' is ambiguous
   35 |         amsynthrc_fname = filesystem::get().config;
      |                           ^
src/filesystem.h:27:7: note: candidate found by name lookup is 'filesystem'
   27 | class filesystem
      |       ^
/usr/include/c++/v1/__chrono/file_clock.h:49:1: note: candidate found by
name lookup is 'std::filesystem'
   49 | _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
      | ^
/usr/include/c++/v1/__config:892:80: note: expanded from macro
'_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM'
  892 |                                              inline namespace __fs
{ namespace filesystem {
      |
           ^
src/Configuration.cpp:60:22: error: reference to 'filesystem' is ambiguous
   60 |         current_bank_file = filesystem::get().default_bank;
      |                             ^
src/filesystem.h:27:7: note: candidate found by name lookup is 'filesystem'
   27 | class filesystem
      |       ^
/usr/include/c++/v1/__chrono/file_clock.h:49:1: note: candidate found by
name lookup is 'std::filesystem'
   49 | _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
      | ^
/usr/include/c++/v1/__config:892:80: note: expanded from macro
'_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM'
  892 |                                              inline namespace __fs
{ namespace filesystem {
      |
           ^
2 errors generated.
gmake[2]: *** [Makefile:3376: src/amsynth_dssi_gtk-Configuration.o] Error 1
gmake[2]: *** Waiting for unfinished jobs....
src/PresetController.cpp:474:9: error: reference to 'filesystem' is
ambiguous
  474 |         return filesystem::get().user_banks;
      |                ^
src/filesystem.h:27:7: note: candidate found by name lookup is 'filesystem'
   27 | class filesystem
      |       ^
/usr/include/c++/v1/__chrono/file_clock.h:49:1: note: candidate found by
name lookup is 'std::filesystem'
   49 | _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
      | ^
/usr/include/c++/v1/__config:892:80: note: expanded from macro
'_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM'
  892 |                                              inline namespace __fs
{ namespace filesystem {
      |
           ^
mv -f src/.deps/amsynth-AudioOutput.Tpo src/.deps/amsynth-AudioOutput.Po
1 error generated.
---

-- 
Nuno Teixeira
FreeBSD UNIX:  <eduardo@FreeBSD.org>   Web:  https://FreeBSD.org