Cannot install Lxml on Mac OS X 10.9

I want to install Lxml so I can then install Scrapy.

When I updated my Mac today it wouldn't let me reinstall lxml, I get the following error:

In file included from src/lxml/lxml.etree.c:314:
/private/tmp/pip_build_root/lxml/src/lxml/includes/etree_defs.h:9:10: fatal error: 'libxml/xmlversion.h' file not found
#include "libxml/xmlversion.h"
         ^
1 error generated.
error: command 'cc' failed with exit status 1

I have tried using brew to install libxml2 and libxslt, both installed fine but I still cannot install lxml.

Last time I was installing I needed to enable the developer tools on Xcode but since it's updated to Xcode 5 it doesn't give me that option anymore.

Does anyone know what I need to do?

You should install or upgrade the commandline tool for Xcode. Try this in a terminal:

xcode-select --install

I solved this issue on Yosemite by both installing and linking libxml2 and libxslt through brew:

brew install libxml2
brew install libxslt
brew link libxml2 --force
brew link libxslt --force

If you have solved the problem using this method but it pops up again at a later time, you might need to run this before the four lines above:

brew unlink libxml2
brew unlink libxslt

If you are having permission errors with Homebrew, especially on El Capitan, this is a helpful document. In essence, regardless of OS X version, try running:

sudo chown -R $(whoami):admin /usr/local