Receiver networking and compatibility

Six UxPlay files, modified for AirSofa: compat.c/.h, sockets.h,
threads.h and mdnsd.c/.h. Each file is individually licensed under
LGPL-2.1-or-later. The full license is under “GNU LGPL 2.1 — full license”.

Source: https://github.com/FDH2/UxPlay/tree/44024fe07f7f61d459de383e8a1047acdb0c7555/lib

AirSofa modification record:

lib/compat.c - 2026-09-21: explicit Unicode error conversion and C99
formatting for Windows socket errors.
lib/mdnsd/mdnsd.c - 2026-10-01: pointer-width Windows sockets, mDNS
address/NSEC replies and TTLs, TTL-zero withdrawal and stop/join lifecycle.
lib/mdnsd/mdnsd.c - 2026-10-05: routed IPv4 fallback when desktop adapter
selection finds no usable address; reject startup without either host address.
lib/compat.h - 2026-10-05: identifies the prepared MSVC strdup and C99
snprintf compatibility changes with a prominent dated source notice.
lib/sockets.h - 2026-10-05: identifies pointer-width socket handles and
Windows select arguments with a prominent dated source notice.
lib/threads.h - 2026-10-05: identifies native Windows threading helper
selection with a prominent dated source notice.
lib/mdnsd/mdnsd.h - 2026-10-05: selected IPv4 diagnostic API, with a
prominent dated source notice.

The three header notices were added on 2026-10-05 to identify existing
portability changes. The preparation script retains the original notices
and leaves the checksum-pinned input files unchanged. Generated LGPL files
remain under their original licenses.

The separately authored Windows threading helper carries this notice:
/* AirSofa Windows implementation of UxPlay's small threading abstraction.
   Copyright 2026 AirPray contributors. No pthread DLL is required. */

Original per-file copyright and permission notices:

lib/compat.c

/*
 * Copyright (c) 2024 F. Duncanh, All Rights Reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 *==================================================================
 */

lib/compat.h
/**
 *  Copyright (C) 2011-2012  Juho Vähä-Herttua
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 */

lib/mdnsd/mdnsd.c
/**
 *  Copyright (C) 2026  kgbook
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 */

lib/mdnsd/mdnsd.h
/**
 *  Copyright (C) 2026  kgbook
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 */

lib/sockets.h
/**
 *  Copyright (C) 2011-2012  Juho Vähä-Herttua
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 */

lib/threads.h
/**
 *  Copyright (C) 2011-2012  Juho Vähä-Herttua
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *=================================================================
 * modified by fduncanh 2022
 */