What I did on my Linux raspberrypi 4.14.79-v7+:
sudo apt-get install libxslt-dev libxml2-dev python3-lxml
sudo su -s /bin/bash homeassistant
source /srv/homeassistant/bin/activate
(homeassistant) pi@hassbian:/usr/bin $ pip3 install lxml
First error thrown:
arm-linux-gnueabihf-gcc -pthread -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -g -fdebug-prefix-map=/build/python3.5-6waWnr/python3.5-3.5.3=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -fPIC -DCYTHON_CLINE_IN_TRACEBACK=0 -I/usr/include/libxml2 -Isrc -Isrc/lxml/includes -I/srv/homeassistant/include -I/usr/include/python3.5m -c src/lxml/etree.c -o build/temp.linux-armv7l-3.5/src/lxml/etree.o -w
In file included from /usr/include/libxslt/xsltInternals.h:24:0,
from src/lxml/etree.c:738:
/usr/include/libxslt/xsltlocale.h:20:21: fatal error: xlocale.h: Datei oder Verzeichnis nicht gefunden
#include <xlocale.h>
^
compilation terminated.
Compile failed: command 'arm-linux-gnueabihf-gcc' failed with exit status 1
creating tmp
cc -I/usr/include/libxml2 -I/usr/include/libxml2 -c /tmp/xmlXPathInitmixl_79w.c -o tmp/xmlXPathInitmixl_79w.o
/tmp/xmlXPathInitmixl_79w.c:2:1: warning: return type defaults to ‘int’ [-Wimplicit-int]
main (int argc, char **argv) {
^~~~
cc tmp/xmlXPathInitmixl_79w.o -lxml2 -o a.out
error: command 'arm-linux-gnueabihf-gcc' failed with exit status 1
----------------------------------------
Failed building wheel for lxml