v0.31.0: Undefined symbol "call_once" on FreeBSD 15

first things first: thanks for the great software!

my issue:
installed under python 3.12 via pip on FreeBSD 15.1-p1:

Collecting asyncpg==0.31.0
  Using cached asyncpg-0.31.0-cp312-cp312-freebsd_15_1_release_p1_amd64.whl
Installing collected packages: asyncpg
...

results in this:

    import asyncpg
  File "/usr/home/l9/py312/lib/python3.12/site-packages/asyncpg/__init__.py", line 9, in <module>
    from .connection import connect, Connection  # NOQA
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/home/l9/py312/lib/python3.12/site-packages/asyncpg/connection.py", line 25, in <module>
    from . import connect_utils
  File "/usr/home/l9/py312/lib/python3.12/site-packages/asyncpg/connect_utils.py", line 33, in <module>
    from . import protocol
  File "/usr/home/l9/py312/lib/python3.12/site-packages/asyncpg/protocol/__init__.py", line 11, in <module>
    from .protocol import Protocol, NO_TIMEOUT, BUILTIN_TYPE_NAME_MAP
ImportError: /usr/home/l9/py312/lib/python3.12/site-packages/asyncpg/protocol/protocol.cpython-312.so: Undefined symbol "call_once"

python3.12/site-packages/asyncpg/protocol/protocol.cpython-312.so:
	libthr.so.3 => /lib/libthr.so.3 (0x103df0c5a000)
	libc.so.7 => /lib/libc.so.7 (0x103df255f000)
	libsys.so.7 => /lib/libsys.so.7 (0x103df2bb6000)

None of the three libs contains the call_once symbol.
Some link error / missconfiguration?!

在 FreeBSD 15.1-p1 上重现 Python 3.12 导入失败，并使用 ldd 检查 asyncpg/protocol/protocol.cpython-312.so，沿着 asyncpg/init.py、connection.py 和 connect_utils.py 中的导入进行跟踪。追查打包 wheel 中 call_once 未解析的原因，然后验证修正后的 FreeBSD 安装能够成功导入，并保留现有的平台覆盖范围。