fixed #1184 - now cython gets -L of NDK's libraries

[maho]

I noticed that cython fails with error mentioned in #1184 , but workaround is to build kivy first, which copy libpython3.5m.so to .buildozer, and then add cython to requirements.

Solution is, to add NDK path to -L path for compiler/linker. So I did it.

[AndreMiras]

Thanks for the pull request, I've left a comment regarding the Python version that should not be hardcoded so it also works with e.g. 3.6.
Also make sure to run tox so the linter is happy. See Travis errors here https://travis-ci.org/kivy/python-for-android/jobs/403478690

pep8 create: /home/travis/build/kivy/python-for-android/.tox/pep8
pep8 installdeps: flake8
pep8 runtests: commands[0] | flake8 pythonforandroid/
pythonforandroid/recipes/cymunk/__init__.py:12:4: W291 trailing whitespace
pythonforandroid/recipes/cymunk/__init__.py:13:1: E101 indentation contains mixed spaces and tabs
pythonforandroid/recipes/cymunk/__init__.py:13:1: W191 indentation contains tabs
pythonforandroid/recipes/cymunk/__init__.py:15:1: W191 indentation contains tabs
pythonforandroid/recipes/cymunk/__init__.py:15:2: E101 indentation contains mixed spaces and tabs
pythonforandroid/recipes/cymunk/__init__.py:16:1: E101 indentation contains mixed spaces and tabs
pythonforandroid/recipes/cymunk/__init__.py:21:1: E101 indentation contains mixed spaces and tabs
pythonforandroid/recipes/cymunk/__init__.py:21:1: W191 indentation contains tabs
pythonforandroid/recipes/cymunk/__init__.py:22:1: W191 indentation contains tabs
pythonforandroid/recipes/cymunk/__init__.py:22:2: E101 indentation contains mixed spaces and tabs
pythonforandroid/recipes/cymunk/__init__.py:24:1: E101 indentation contains mixed spaces and tabs
ERROR: InvocationError: '/home/travis/build/kivy/python-for-android/.tox/pep8/bin/flake8 pythonforandroid/'
___________________________________ summary ____________________________________
ERROR:   pep8: commands failed
The command "tox" failed and exited with 1 during .
Your build has been stopped.

[AndreMiras]

Also now I'm thinking, perhaps you should give a try to #793 because with it your change my not be needed. Could you try and let us know?

[AndreMiras]

Thanks for the pull request. We recently merged #793 which should also fix it for you. Could you buildozer android update from p4a master (p4a.branch = master) and let us know if it fixes the issue?

[AndreMiras]

Could you rely on the Python version rather than hardcoding 3.5? Because it could also be 3.6 for instance.

[maho]

current master works without this PR, so is no longer needed