title: Installing pycurl with 'fatal error: gnutls/gnutls.h: No such file or directory'
body: <p>I use ubuntu 16.04 and python 2.7.12.</p>
  
  <p>When I try to install pycurl with pip, I could see below log.</p>
  
  <pre><code>aaa@bbb:~/git/ccc$ sudo pip install pycurl
    Downloading pycurl-7.43.0.tar.gz (182kB)
      100% |████████████████████████████████| 184kB 515kB/s 
  Installing collected packages: pycurl
    Running setup.py install for pycurl ... error
  
  ...
  
      In file included from src/docstrings.c:4:0:
      src/pycurl.h:173:30: fatal error: gnutls/gnutls.h: No such file or directory
      compilation terminated.
  </code></pre>
  
  <p>How to install pycurl with above log?</p>