In file included from src/lxml/lxml.etree.c:515:0:
    src/lxml/includes/etree_defs.h:14:31: fatal error: libxml/xmlversion.h: No such file or directory
     #include "libxml/xmlversion.h"
                                   ^
    compilation terminated.
    Compile failed: command 'arm-linux-gnueabihf-gcc' failed with exit status 1
    cc -I/usr/include/libxml2 -c /tmp/xmlXPathInitf8s851u3.c -o tmp/xmlXPathInitf8s851u3.o
    cc tmp/xmlXPathInitf8s851u3.o -lxml2 -o a.out
    error: command 'arm-linux-gnueabihf-gcc' failed with exit status 1

    ----------------------------------------
Command "/home/pi/home-assistant/env/bin/python3 -u -c "import setuptools, tokenize;__file__='/tmp/pip-build-11kfuh1f/lxml/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" install --record /tmp/pip-p55x_cgo-record/install-record.txt --single-version-externally-managed --compile --install-headers /home/pi/home-assistant/env/include/site/python3.4/lxml" failed with error code 1 in /tmp/pip-build-11kfuh1f/lxml/