Compilation on FreeBSD fails: error: 'free_sized' is missing exception specification 'throw()'

Compilation on FreeBSD 16 which has an updated toolchain fails with these errors:

/wrkdirs/usr/ports/math/lean4/work/lean4-4.31.0/stage0/src/runtime/object.cpp:64:28: error: 'free_sized' is missing exception specification 'throw()'
   64 | __attribute__((weak)) void free_sized(void *ptr, size_t) {
      |                            ^
      |                                                          throw()
/wrkdirs/usr/ports/math/lean4/work/.build/stage0/include/lean/lean.h:475:6: note: previous declaration is here
  475 | void free_sized(void* ptr, size_t);
      |      ^
/wrkdirs/usr/ports/math/lean4/work/lean4-4.31.0/stage0/src/runtime/object.cpp:267:5: error: call to 'free_sized' is ambiguous
  267 |     free_sized(o, sz);
      |     ^~~~~~~~~~
/wrkdirs/usr/ports/math/lean4/work/.build/stage0/include/lean/lean.h:475:6: note: candidate function
  475 | void free_sized(void* ptr, size_t);
      |      ^
/wrkdirs/usr/ports/math/lean4/work/lean4-4.31.0/stage0/src/runtime/object.cpp:64:28: note: candidate function
   64 | __attribute__((weak)) void free_sized(void *ptr, size_t) {
      |                            ^
2 errors generated.

Reproduce the FreeBSD 16 build and inspect stage0/src/runtime/object.cpp alongside the generated stage0/include/lean/lean.h declaration of free_sized. Trace why the declaration and definition differ under the updated toolchain, then verify that the stage0 compilation completes without the ambiguity or exception-specification errors.