title: Build Error while converting python file into apk using buildozer
body: <p>I have made a simple app in python using Kivy and now I want this to be converted into an apk file so that I can use it in my android mobile.
  But constantly I am getting following build error while converting it. I am using buildozer for building an apk file.
  I have checked for any missing files or directory, but that's not the case. OS : UBUNTU 12.04. The Error is :</p>
  
  <pre><code>[aapt] ~/.buildozer/android/platform/android-sdk-21/platform-tools/aapt: error while loading shared libraries: libz.so.1: cannot open shared object file: No such file or directory
  
  BUILD FAILED
  ~/.buildozer/android/platform/android-sdk-21/tools/ant/build.xml:645: The following error occurred while executing this line:
  ~/.buildozer/android/platform/android-sdk-21/tools/ant/build.xml:683: null returned: 127
  
  Total time: 1 second
  .
  .
  .
  assets/private.mp3: /home/manish/kivy/.buildozer/android/app/sitecustomize.pyo
  Traceback (most recent call last):
    File "build.py", line 412, in &lt;module&gt;
      make_package(args)
    File "build.py", line 336, in make_package
      subprocess.check_call([ANT, arg])
    File "/usr/lib/python2.7/subprocess.py", line 511, in check_call
      raise CalledProcessError(retcode, cmd)
  subprocess.CalledProcessError: Command '['ant', 'debug']' returned non-zero exit status 1
  # Command failed: /usr/bin/python2.7 build.py --name 'My Application' --version 1.0 --package org.test.myapp --private /home/manish/kivy/.buildozer/android/app --sdk 14 --minsdk 8 --orientation landscape --window debug
  </code></pre>