Nokogiri gem failing to install - ruby-on-rails

Question

I'm trying to install nokogiri v 1.6.7.2 in a new rails project. I'm running Kali Linux (debian-based). Here is the stack trace:
$ gem install nokogiri -v '1.6.7.2' -- --use-system-libraries
Building native extensions with: '--use-system-libraries'
This could take a while...
ERROR: Error installing nokogiri:
ERROR: Failed to build gem native extension.
/usr/bin/ruby2.2 -r ./siteconf20160405-3609-rdkvif.rb extconf.rb --use-system-libraries
checking if the C compiler accepts ... yes
Building nokogiri using system libraries.
libxml2 version 2.6.21 or later is required!
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers. Check the mkmf.log file for more details. You may
need configuration options.
Provided configuration options:
--with-opt-dir
--without-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/usr/bin/$(RUBY_BASE_NAME)2.2
--help
--clean
--use-system-libraries
--with-zlib-dir
--without-zlib-dir
--with-zlib-include
--without-zlib-include=${zlib-dir}/include
--with-zlib-lib
--without-zlib-lib=${zlib-dir}/lib
--with-xml2-dir
--without-xml2-dir
--with-xml2-include
--without-xml2-include=${xml2-dir}/include
--with-xml2-lib
--without-xml2-lib=${xml2-dir}/lib
--with-libxml-2.0-config
--without-libxml-2.0-config
--with-pkg-config
--without-pkg-config
--with-xslt-dir
--without-xslt-dir
--with-xslt-include
--without-xslt-include=${xslt-dir}/include
--with-xslt-lib
--without-xslt-lib=${xslt-dir}/lib
--with-libxslt-config
--without-libxslt-config
--with-pkg-config
--without-pkg-config
--with-exslt-dir
--without-exslt-dir
--with-exslt-include
--without-exslt-include=${exslt-dir}/include
--with-exslt-lib
--without-exslt-lib=${exslt-dir}/lib
--with-libexslt-config
--without-libexslt-config
--with-pkg-config
--without-pkg-config
extconf failed, exit code 1
Gem files will remain installed in /var/lib/gems/2.2.0/gems/nokogiri-1.6.7.2 for inspection.
Results logged to /var/lib/gems/2.2.0/extensions/x86_64-linux/2.2.0/nokogiri-1.6.7.2/gem_make.out
I've checked I have libxml2 installed:
apt-get install libxml2
Reading package lists... Done
Building dependency tree
Reading state information... Done
libxml2 is already the newest version (2.9.3+dfsg1-1).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
And I saw in other threads to try using the --use-sytem-libraries flag, but that still causes the same error. What am I missing?
Thank you!

Answer 1

In addition to libxml2 and libxslt, you also require some additional development libraries. Install them using sudo apt-get install ruby-dev zlib1g-dev liblzma-dev. More at https://github.com/sparklemotion/nokogiri.org-tutorials/blob/master/content/installing_nokogiri.md.