message: Adds XOPEN_SOURCE for PATH_MAX and POSIX 1993 for stat
  * Adds XOPEN_SOURCE for PATH_MAX and POSIX 1993 for stat
  These are the only two required extension for compilation of
  flatbuffers using -std=c++11 instead of gnu++11.
  * Sets _XOPEN_SOURCE to 600 and enable POSIX2001 for fseeko
diff: // clang-format off
  // Dont't remove `format off`, it prevent reordering of win-includes.
  +#define _POSIX_C_SOURCE 200112L // For stat from stat/stat.h and fseeko() (POSIX extensions).
  #ifdef _WIN32
  # ifndef WIN32_LEAN_AND_MEAN
  # define WIN32_LEAN_AND_MEAN
  # include <winbase.h>
  # undef interface // This is also important because of reasons
  #else
  +# define _XOPEN_SOURCE 600 // For PATH_MAX from limits.h (SUSv2 extension)
  # include <limits.h>
  #endif
  // clang-format on
  