Adopting a pre-bound socket via SetReservedListenSocket left Worker()'s
port bookkeeping untouched, so GetPort() and the broadcast announcement
reported the computed default instead of the port the socket listens on.
The monitor kept this correct by mirroring the reserved port into
TRACY_PORT; direct users of the public API had no such coupling.
The bound socket is now authoritative: Worker() reads the local port
back via getsockname after binding. The search-loop bookkeeping stays
only as a fallback for a getsockname failure.
Replace `#ifdef BSD` (which requires including `<sys/param.h>` first) with explicit checks for `__FreeBSD__`, `__NetBSD__`, `__OpenBSD__` and `__DragonFly__`, matching how these BSDs are already enumerated elsewhere in the codebase (OS name strings, thread id helpers, etc.).
This also avoids leaking the `sys/param.h` requirement through public headers (`TracySysTime.hpp`, `TracyCallstack.h`), where consumers would otherwise need it to correctly see `TRACY_HAS_SYSTIME` / `TRACY_HAS_CALLSTACK`.
`libbacktrace/config.h` is left as-is — it's third-party and only included from .c files where the `BSD` macro can still be picked up locally.
Note: for `setsockopt( m_sock, IPPROTO_IPV6, IPV6_V6ONLY, (const char*)&val, sizeof( val ) );` I added `__APPLE__` too since this was the only place where it was not checked explicitely.
