Fixed #5645: realloc return handling
const unsigned char* lodepng_chunk_next_const(const unsigned char* chunk)
{
  unsigned total_chunk_length = lodepng_chunk_length(chunk) + 12;
  return &chunk[total_chunk_length];
}

const unsigned char* lodepng_chunk_next_const(const unsigned char* chunk)
{
  unsigned total_chunk_length = lodepng_chunk_length(chunk) + 12;
  return &chunk[total_chunk_length];
}
