cant install nokogiri on ubuntu 14.04.3 lts

[ali]

Hi

I cannot install nokogiri on ubuntu 14.04.3 lts.

Building native extensions.  This could take a while...

ERROR:  Error installing nokogiri:

        ERROR: Failed to build gem native extension.

    current directory: /usr/local/rvm/gems/ruby-2.3.0/gems/nokogiri-1.6.8/ext/nokogiri

/usr/local/rvm/rubies/ruby-2.3.0/bin/ruby -r ./siteconf20161001-37359-ybmwak.rb extconf.rb

Using pkg-config version 1.1.7

checking if the C compiler accepts -ggdb3 -O0 -std=c11 -Wall -Werror -Wshadow... yes

Building nokogiri using packaged libraries.

Using mini_portile version 2.1.0

checking for gzdopen() in -lz... yes

checking for iconv... yes

************************************************************************

IMPORTANT NOTICE:

Building Nokogiri with a packaged version of libxml2-2.9.4.

Team Nokogiri will keep on doing their best to provide security

updates in a timely manner, but if this is a concern for you and want

to use the system library instead; abort this installation process and

reinstall nokogiri as follows:

    gem install nokogiri -- --use-system-libraries

        [--with-xml2-config=/path/to/xml2-config]

        [--with-xslt-config=/path/to/xslt-config]

If you are using Bundler, tell it to use the option:

    bundle config build.nokogiri --use-system-libraries

    bundle install

Note, however, that nokogiri is not fully compatible with arbitrary

versions of libxml2 provided by OS/package vendors.

************************************************************************

Extracting libxml2-2.9.4.tar.gz into tmp/x86_64-pc-linux-gnu/ports/libxml2/2.9.4... OK

Running 'configure' for libxml2 2.9.4... OK

Running 'compile' for libxml2 2.9.4... ERROR, review '/usr/local/rvm/gems/ruby-2.3.0/gems/nokogiri-1.6.8/ext/nokogiri/tmp/x86_64-pc-linux-gnu/ports/libxml2/2.9.4/compile.log' to see what happened. Last lines are:

========================================================================

  CC       entities.lo

  CC       encoding.lo

encoding.c:491:26: error: cast from 'const unsigned char *' to 'unsigned short *' increases required alignment from 1 to 2 [-Werror,-Wcast-align]

    unsigned short* in = (unsigned short*) inb;

                         ^~~~~~~~~~~~~~~~~~~~~

encoding.c:573:27: error: cast from 'unsigned char *' to 'unsigned short *' increases required alignment from 1 to 2 [-Werror,-Wcast-align]

    unsigned short* out = (unsigned short*) outb;

                          ^~~~~~~~~~~~~~~~~~~~~~

encoding.c:729:26: error: cast from 'const unsigned char *' to 'unsigned short *' increases required alignment from 1 to 2 [-Werror,-Wcast-align]

    unsigned short* in = (unsigned short*) inb;

                         ^~~~~~~~~~~~~~~~~~~~~

encoding.c:815:27: error: cast from 'unsigned char *' to 'unsigned short *' increases required alignment from 1 to 2 [-Werror,-Wcast-align]

    unsigned short* out = (unsigned short*) outb;

                          ^~~~~~~~~~~~~~~~~~~~~~

4 errors generated.

make[2]: *** [encoding.lo] Error 1

make[2]: Leaving directory `/usr/local/rvm/gems/ruby-2.3.0/gems/nokogiri-1.6.8/ext/nokogiri/tmp/x86_64-pc-linux-gnu/ports/libxml2/2.9.4/libxml2-2.9.4'

make[1]: *** [all-recursive] Error 1

make[1]: Leaving directory `/usr/local/rvm/gems/ruby-2.3.0/gems/nokogiri-1.6.8/ext/nokogiri/tmp/x86_64-pc-linux-gnu/ports/libxml2/2.9.4/libxml2-2.9.4'

make: *** [all] Error 2

========================================================================

*** 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/local/rvm/rubies/ruby-2.3.0/bin/$(RUBY_BASE_NAME)

        --help

        --clean

        --use-system-libraries

        --enable-static

        --disable-static

        --with-zlib-dir

        --without-zlib-dir

        --with-zlib-include

        --without-zlib-include=${zlib-dir}/include

        --with-zlib-lib

        --without-zlib-lib=${zlib-dir}/lib

        --enable-cross-build

        --disable-cross-build

/usr/local/rvm/gems/ruby-2.3.0/gems/mini_portile2-2.1.0/lib/mini_portile2/mini_portile.rb:366:in `block in execute': Failed to complete compile task (RuntimeError)

        from /usr/local/rvm/gems/ruby-2.3.0/gems/mini_portile2-2.1.0/lib/mini_portile2/mini_portile.rb:337:in `chdir'

        from /usr/local/rvm/gems/ruby-2.3.0/gems/mini_portile2-2.1.0/lib/mini_portile2/mini_portile.rb:337:in `execute'

        from /usr/local/rvm/gems/ruby-2.3.0/gems/mini_portile2-2.1.0/lib/mini_portile2/mini_portile.rb:111:in `compile'

        from /usr/local/rvm/gems/ruby-2.3.0/gems/mini_portile2-2.1.0/lib/mini_portile2/mini_portile.rb:150:in `cook'

        from extconf.rb:364:in `block (2 levels) in process_recipe'

        from extconf.rb:257:in `block in chdir_for_build'

        from extconf.rb:256:in `chdir'

        from extconf.rb:256:in `chdir_for_build'

        from extconf.rb:363:in `block in process_recipe'

        from extconf.rb:262:in `tap'

        from extconf.rb:262:in `process_recipe'

        from extconf.rb:555:in `<main>'

To see why this extension failed to compile, please check the mkmf.log which can be found here:

  /usr/local/rvm/gems/ruby-2.3.0/extensions/x86_64-linux/2.3.0/nokogiri-1.6.8/mkmf.log

extconf failed, exit code 1

Gem files will remain installed in /usr/local/rvm/gems/ruby-2.3.0/gems/nokogiri-1.6.8 for inspection.

Results logged to /usr/local/rvm/gems/ruby-2.3.0/extensions/x86_64-linux/2.3.0/nokogiri-1.6.8/gem_make.out

I am getting this error. Whats wrong?