libmpg123 library version 1.30.2 (2022-08-01).
The following changes have been made:
- ports/makefile/config.h and ports/makefile/mpg123.h have been added for plain
  Makefile builds.
- ports/MSVC++/config.h and ports/MSVC++/mpg123.h have been retained from older
  versions.
- ports/Xcode/config.h and ports/MSVC++/mpg123.h have been retained from older
  versions.
- ports/MSVC++/config.h has been modified to define OFF_MAX.
- ports/MSVC++/mpg123.h has been adjusted to provide mpg123_ssize_t and define
  MPG123_NO_LARGENAME.
- ports/Xcode/mpg123.h has been adjusted to provide mpg123_ssize_t and define
  MPG123_API_VERSION
- src/libmpg123/mpg123.h.in has been modified to #include <fmt123.h> as
  #include "fmt123.h"
- ports/Xcode/config.h has been modified to let the build system set OPT_*
- ports/Xcode/config.h has been modified to #define HAVE_DIRENT_H.
- Modifications are marked by // OpenMPT or /* OpenMPT */.
- Obviously, unnecessary folders and files have been removed.
- For building, premake is used to generate Visual Studio project files.
  See ../build/premake/ for details.
