Mountain Lion にしてから bundle install とか gem install とか rvm 周りでエラーが出る件

gistfile1.txt

~/work/test]$ bundle install
Fetching gem metadata from http://rubygems.org/......
Fetching gem metadata from http://rubygems.org/..
Using rake (0.9.2.2) 
Using i18n (0.6.1) 
    :
  (中略)
    :
Installing hpricot (0.8.6) with native extensions 
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.

        /Users/imaz/.rvm/rubies/ruby-1.9.3-p194/bin/ruby 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
	--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/imaz/.rvm/rubies/ruby-1.9.3-p194/bin/ruby
/Users/imaz/.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/imaz/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:506:in `try_cpp'
	from /Users/imaz/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:931:in `block in have_header'
	from /Users/imaz/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:790:in `block in checking_for'
	from /Users/imaz/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:284:in `block (2 levels) in postpone'
	from /Users/imaz/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:254:in `open'
	from /Users/imaz/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:284:in `block in postpone'
	from /Users/imaz/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:254:in `open'
	from /Users/imaz/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:280:in `postpone'
	from /Users/imaz/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:789:in `checking_for'
	from /Users/imaz/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:930:in `have_header'
	from extconf.rb:2:in `<main>'


Gem files will remain installed in /Users/imaz/.rvm/gems/ruby-1.9.3-p194/gems/hpricot-0.8.6 for inspection.
Results logged to /Users/imaz/.rvm/gems/ruby-1.9.3-p194/gems/hpricot-0.8.6/ext/fast_xs/gem_make.out
An error occurred while installing hpricot (0.8.6), and Bundler cannot continue.
Make sure that `gem install hpricot -v '0.8.6'` succeeds before bundling.
[~/work/test]$ gem install hpricot -v '0.8.6'
Building native extensions.  This could take a while...
ERROR:  Error installing hpricot:
	ERROR: Failed to build gem native extension.

        /Users/imaz/.rvm/rubies/ruby-1.9.3-p194/bin/ruby 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
	--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/imaz/.rvm/rubies/ruby-1.9.3-p194/bin/ruby
/Users/imaz/.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/imaz/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:506:in `try_cpp'
	from /Users/imaz/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:931:in `block in have_header'
	from /Users/imaz/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:790:in `block in checking_for'
	from /Users/imaz/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:284:in `block (2 levels) in postpone'
	from /Users/imaz/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:254:in `open'
	from /Users/imaz/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:284:in `block in postpone'
	from /Users/imaz/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:254:in `open'
	from /Users/imaz/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:280:in `postpone'
	from /Users/imaz/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:789:in `checking_for'
	from /Users/imaz/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:930:in `have_header'
	from extconf.rb:2:in `<main>'


Gem files will remain installed in /Users/imaz/.rvm/gems/ruby-1.9.3-p194/gems/hpricot-0.8.6 for inspection.
Results logged to /Users/imaz/.rvm/gems/ruby-1.9.3-p194/gems/hpricot-0.8.6/ext/fast_xs/gem_make.out

bundle install --binstubs
gem install hpricot -v '0.8.6'
　⇒エラー！ エラー！ ここの内容。

https://developer.apple.com/downloads/index.actionダウンロード: Xcode 4.5.2
　⇒まだ直らない
ダウンロード: Command Line Tools (OS X Mountain Lion) for Xcode - November 2012
　⇒まだ直らない
$ xcodebuild -version
xcrun: Error: failed to exec real xcrun. (No such file or directory)
　⇒ほむ？
http://stackoverflow.com/questions/11977648/xcrun-error-failed-to-exec-real-xcrun-no-such-file-or-directory
$ sudo xcode-select -switch /Applications/Xcode.app/Contents/Developer/
　⇒あっ！ これ最近見たやつだ！
$ xcodebuild -version
Xcode 4.5.2
Build version 4G2008a
　⇒おお！