title: Cannot install pycosat on alpine during dockerizing
body: <p>I am trying to dockerize django application, and I am using <strong>alpine:edge</strong> as base image. And <strong>pycosat</strong> installation fails with error </p>
  
  <pre><code>In file included from pycosat.c:19:
  picosat.c:8150:10: fatal error: sys/unistd.h: No such file or directory
   #include &lt;sys/unistd.h&gt;
            ^~~~~~~~~~~~~~
  compilation terminated.
  error: Setup script exited with error: command 'gcc' failed with exit status 1
  </code></pre>
  
  <p>Here how is my Dockerfile looks like</p>
  
  <pre><code>FROM alpine:edge
      ENV PYTHONBUFFERED 1
  
      RUN apk update &amp;&amp; \
          apk add --virtual build-deps gcc python3-dev musl-dev \
          libffi-dev openssl-dev python3 py3-zmq build-base libzmq zeromq-dev \
          curl g++ make zlib-dev linux-headers openssl ca-certificates libevent-dev
  
      RUN pip3 install --upgrade pip setuptools
      RUN mkdir /config
      ADD /config/requirements.txt /config/
      RUN easy_install pyzmq
      RUN easy_install pycosat
      RUN mkdir /src
      WORKDIR /src
  </code></pre>
  
  <p>How can I make it to install this lib? Do I miss some packages or utils or something?</p>
  
  <p>Also I am using docker-compose to build it</p>