git-whistles error

Fetching: nokogiri-happymapper-0.5.9.gem (100%)
Successfully installed nokogiri-happymapper-0.5.9
Fetching: safe_yaml-1.0.3.gem (100%)
Successfully installed safe_yaml-1.0.3
Fetching: crack-0.4.2.gem (100%)
Successfully installed crack-0.4.2
Fetching: libxml-ruby-2.7.0.gem (100%)
Building native extensions.  This could take a while...
ERROR:  Error installing git-whistles:
	ERROR: Failed to build gem native extension.

    /Users/shariff/.rvm/rubies/ruby-1.9.3-p429/bin/ruby extconf.rb
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
	--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/shariff/.rvm/rubies/ruby-1.9.3-p429/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/shariff/.rvm/rubies/ruby-1.9.3-p429/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/shariff/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:461:in `try_link0'
	from /Users/shariff/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:476:in `try_link'
	from /Users/shariff/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:619:in `try_func'
	from /Users/shariff/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:845:in `block in have_library'
	from /Users/shariff/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:790:in `block in checking_for'
	from /Users/shariff/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:284:in `block (2 levels) in postpone'
	from /Users/shariff/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:254:in `open'
	from /Users/shariff/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:284:in `block in postpone'
	from /Users/shariff/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:254:in `open'
	from /Users/shariff/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:280:in `postpone'
	from /Users/shariff/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:789:in `checking_for'
	from /Users/shariff/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/mkmf.rb:840:in `have_library'
	from extconf.rb:29:in `<main>'