# gem install ronn
Building native extensions.  This could take a while...
ERROR:  Error installing ronn:
        ERROR: Failed to build gem native extension.

    /usr/local/rvm/rubies/ruby-2.2.3-dev/bin/ruby -r ./siteconf20150827-26083-1m1iqbt.rb extconf.rb
checking for stdio.h... *** 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-2.2.3-dev/bin/$(RUBY_BASE_NAME)
/usr/local/rvm/rubies/ruby-2.2.3-dev/lib/ruby/2.2.0/mkmf.rb:456:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
        from /usr/local/rvm/rubies/ruby-2.2.3-dev/lib/ruby/2.2.0/mkmf.rb:587:in `try_cpp'
        from /usr/local/rvm/rubies/ruby-2.2.3-dev/lib/ruby/2.2.0/mkmf.rb:1060:in `block in have_header'
        from /usr/local/rvm/rubies/ruby-2.2.3-dev/lib/ruby/2.2.0/mkmf.rb:911:in `block in checking_for'
        from /usr/local/rvm/rubies/ruby-2.2.3-dev/lib/ruby/2.2.0/mkmf.rb:351:in `block (2 levels) in postpone'
        from /usr/local/rvm/rubies/ruby-2.2.3-dev/lib/ruby/2.2.0/mkmf.rb:321:in `open'
        from /usr/local/rvm/rubies/ruby-2.2.3-dev/lib/ruby/2.2.0/mkmf.rb:351:in `block in postpone'
        from /usr/local/rvm/rubies/ruby-2.2.3-dev/lib/ruby/2.2.0/mkmf.rb:321:in `open'
        from /usr/local/rvm/rubies/ruby-2.2.3-dev/lib/ruby/2.2.0/mkmf.rb:347:in `postpone'
        from /usr/local/rvm/rubies/ruby-2.2.3-dev/lib/ruby/2.2.0/mkmf.rb:910:in `checking_for'
        from /usr/local/rvm/rubies/ruby-2.2.3-dev/lib/ruby/2.2.0/mkmf.rb:1059:in `have_header'
        from extconf.rb:2:in `<main>'

extconf failed, exit code 1

Gem files will remain installed in /usr/local/rvm/gems/ruby-2.2.3-dev/gems/hpricot-0.8.6 for inspection.
Results logged to /usr/local/rvm/gems/ruby-2.2.3-dev/extensions/x86_64-linux/2.2.0/hpricot-0.8.6/gem_make.out