title: When do I need zlib in OpenSSL?
body: <p>Some site describe config &amp; make for OpenSSL with zlib while I can do it without zlib.</p>
  <p>It means zlib is not necessary for openSSL in some case.</p>
  <p>Does anyone tell me what case OpenSSL does compression or decompression?</p>
  <p>The <a href="https://stackoverflow.com/a/23772857/117259">answer from @Giacomo1968</a> is useful.
  I want to know how to choose if I use –z or not?</p>