nokogiri 1.6.3 install error OSX

README.md

System details

OSX -> 10.9.3

Homebrew

$ brew -v
Homebrew 0.9.5

libxslt

$ brew info libxslt | grep bottled
libxslt: stable 1.1.28 (bottled)

libxml2

$ brew info libxml2 | grep bottled
libxml2: stable 2.9.1 (bottled), HEAD

xcode (version 5.1.1 according to XCode -> About XCode)

$ xcode-select -v
xcode-select version 2333.

gem_make.out

/Users/danial.pearce/.rubies/ruby-2.0.0-p451/bin/ruby extconf.rb --use-system-libraries
Building nokogiri using system libraries.
*** 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/danial.pearce/.rubies/ruby-2.0.0-p451/bin/ruby
	--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
/Users/danial.pearce/.rubies/ruby-2.0.0-p451/lib/ruby/2.0.0/mkmf.rb:434:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
	from /Users/danial.pearce/.rubies/ruby-2.0.0-p451/lib/ruby/2.0.0/mkmf.rb:519:in `try_link0'
	from /Users/danial.pearce/.rubies/ruby-2.0.0-p451/lib/ruby/2.0.0/mkmf.rb:534:in `try_link'
	from /Users/danial.pearce/.rubies/ruby-2.0.0-p451/lib/ruby/2.0.0/mkmf.rb:620:in `block in try_ldflags'
	from /Users/danial.pearce/.rubies/ruby-2.0.0-p451/lib/ruby/2.0.0/mkmf.rb:613:in `with_ldflags'
	from /Users/danial.pearce/.rubies/ruby-2.0.0-p451/lib/ruby/2.0.0/mkmf.rb:619:in `try_ldflags'
	from /Users/danial.pearce/.rubies/ruby-2.0.0-p451/lib/ruby/2.0.0/mkmf.rb:1725:in `pkg_config'
	from extconf.rb:341:in `<main>'

mkmf.log

"gcc-4.2 -o conftest -I/Users/danial.pearce/.rubies/ruby-2.0.0-p451/include/ruby-2.0.0/x86_64-darwin13.0.0 -I/Users/danial.pearce/.rubies/ruby-2.0.0-p451/include/ruby-2.0.0/ruby/backward -I/Users/danial.pearce/.rubies/ruby-2.0.0-p451/include/ruby-2.0.0 -I. -I/Users/danial.pearce/.rubies/ruby-2.0.0-p451/include  -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -D_DARWIN_UNLIMITED_SELECT -D_REENTRANT    -O3 -Wno-error=shorten-64-to-32  -pipe  -Wno-error=unused-command-line-argument-hard-error-in-future -Wall -Wcast-qual -Wwrite-strings -Wconversion -Wmissing-noreturn -Winline conftest.c  -L. -L/Users/danial.pearce/.rubies/ruby-2.0.0-p451/lib -lxml2     -lruby-static  -lpthread -ldl -lobjc  "
cc1: error: -Werror=unused-command-line-argument-hard-error-in-future: No option -Wunused-command-line-argument-hard-error-in-future
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: int main(int argc, char **argv)
4: {
5:   return 0;
6: }
/* end */