Function get_available_RAM

LASzip/src/mydefs.cpp:530–537

/// Note that this value is only a snapshot.
#ifdef _WIN32
size_t get_available_RAM() {
  MEMORYSTATUSEX statex;
  statex.dwLength = sizeof(statex);
  if (GlobalMemoryStatusEx(&statex)) {
    return statex.ullAvailPhys;
  }
  return 0;
}
#else
size_t get_available_RAM() {
  FILE* f = fopen("/proc/meminfo", "r");