xcode - command line tools for new 10.9 OSX for ruby gems?

Question

After installing OSX Mavericks 10.9 demo, Im getting this after running bundle

    Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.

    /Users/sandric/.rvm/rubies/ruby-1.9.3-p194/bin/ruby extconf.rb 
extconf.rb:17: Use RbConfig instead of obsolete and deprecated Config.
checking for socket() in -lsocket... *** 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=/Users/sandric/.rvm/rubies/ruby-1.9.3-p194/bin/ruby
    --with-iconv-dir
    --without-iconv-dir
    --with-iconv-include
    --without-iconv-include=${iconv-dir}/include
    --with-iconv-lib
    --without-iconv-lib=${iconv-dir}/lib
    --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-socketlib
    --without-socketlib
/Users/sandric/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:381:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
    from /Users/sandric/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:461:in `try_link0'
    from /Users/sandric/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:476:in `try_link'
    from /Users/sandric/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:619:in `try_func'
    from /Users/sandric/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:845:in `block in have_library'
    from /Users/sandric/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:790:in `block in checking_for'
    from /Users/sandric/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:284:in `block (2 levels) in postpone'
    from /Users/sandric/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:254:in `open'
    from /Users/sandric/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:284:in `block in postpone'
    from /Users/sandric/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:254:in `open'
    from /Users/sandric/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:280:in `postpone'
    from /Users/sandric/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:789:in `checking_for'
    from /Users/sandric/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:840:in `have_library'
    from extconf.rb:27:in `<main>'


Gem files will remain installed in /Users/sandric/.bundler/tmp/5282/gems/libxml-ruby-2.6.0 for inspection.
Results logged to /Users/sandric/.bundler/tmp/5282/gems/libxml-ruby-2.6.0/ext/libxml/gem_make.out
An error occurred while installing libxml-ruby (2.6.0), and Bundler cannot continue.
Make sure that `gem install libxml-ruby -v '2.6.0'` succeeds before bundling.

I think that I do not have command line tools, so I tried to download some. It found out that there is no usual link for this in my XCode (it is 4, not 5, dont know why. If there is some way of installing fifth xcode - please help). So I went to apple developers webpage and not found command line tools for 10.9. I tried for 10.8 - it prints "Try install for 10.7", after trying with tools for 10.7 - it prints "try for 10.8".

Please, help. I'll provide all info for help.

Answer 1

TLDR:

xcode-select --install

In OS X 10.9, the command line developer tools are now installed on demand when they are used (this is the popup you mention seeing in a later comment).

The first time something tries to use one of the command line tools, the popup will be presented and the original command will return with a message that the command line tools need to be installed and with an error code. In this case, the problem is that the ruby process is hiding the message about the command line tools being needed.

If you wish to explicitly install the command line tools (instead of waiting for the popup to be triggered), you can run xcode-select --install. The command line tools package is also available as an independent download from http://developer.apple.com/downloads.

Note that if you have Xcode installed on your system, you should no longer need the separate command line tools package, the tools in /usr/bin will automatically use the ones located inside of the Xcode application. This is why the Xcode UI no longer offers the option to install the command line tools for you.