Don't link to libpython in linux and osx as they are not needed.
Don't link to libpython in linux and osx as they are not needed.

This is a fix to a bug introduced at 98d7bf85a7cf1a8c3fabf0132970dbd4f79c27e8

bjodah/symengine.py,symengine/symengine.py,bjodah/symengine.py,bjodah/symengine.py,symengine/symengine.py,symengine/symengine.py