the define CURL_MAX_HTTP_HEADER which is even exposed in the public header
  file to allow for users to fairly easy rebuild libcurl with a modified
  limit. The rationale for a fixed limit is that libcurl is realloc()ing a
  buffer to be able to put a full header into it, so that it can call the
  header callback with the entire header, but that also risk getting it into
  trouble if a server by mistake or willingly sends a header that is more or
  less without an end. The limit is set to 100K.