Mac上RoR环境搭建问题

WutekiMacBook-Pro:~ wuxj$ rvm requirements
Checking requirements for osx.
Error: No available formula for gcc46 
Installing requirements for osx.
Updating system.......
Error running ‘requirements_osx_brew_update_system ‘,
showing last 15 lines of /Users/wuxj/.rvm/log/1409358409/update_system.log
    https://github.com/Homebrew/homebrew/wiki/Common-Issues
and make sure `brew update` works before continuing.‘
+ rvm_pretty_print stderr
+ case "${rvm_pretty_print_flag:=auto}" in
+ case "${TERM:-dumb}" in
+ case "$1" in
+ [[ -t 2 ]]
+ return 1
+ printf %b ‘Failed to update Homebrew, follow instructions here:
    https://github.com/Homebrew/homebrew/wiki/Common-Issues
and make sure `brew update` works before continuing.\n‘
Failed to update Homebrew, follow instructions here:
    https://github.com/Homebrew/homebrew/wiki/Common-Issues
and make sure `brew update` works before continuing.
+ return 1
Requirements installation failed with status: 1.

WutekiMacBook-Pro:~ wuxj$ brew update
error: The following untracked working tree files would be overwritten by merge:
    Library/Formula/ant.rb
    Library/Formula/libarchive.rb
Please move or remove them before you can merge.
Aborting
Error: Failure while executing: git pull -q origin refs/heads/master:refs/remotes/origin/master

WutekiMacBook-Pro:~ wuxj$ brew doctor
Warning: Some directories in your path end in a slash.
Directories in your path should not end in a slash. This can break other
doctor checks. The following directories should be edited:
    /Users/wuxj/Downloads/adt-bundle-mac-x86_64-20131030/sdk/platform-tools/
Error: Homebrew doesn‘t know what compiler versions ship with your version
of Xcode (5.1.1). Please `brew update` and if that doesn‘t help, file
an issue with the output of `brew --config`:
  https://github.com/mxcl/homebrew/issues

Thanks!

。
。
。
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

    /Users/wuxj/.rvm/rubies/ruby-2.1.2/bin/ruby -r ./siteconf20140830-1163-1hd6znq.rb extconf.rb 
Building nokogiri using packaged libraries.
-----
libiconv is missing.  please visit http://nokogiri.org/tutorials/installing_nokogiri.html for help with installing dependencies.
-----
*** 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/wuxj/.rvm/rubies/ruby-2.1.2/bin/ruby
    --help
    --clean
    --use-system-libraries
    --enable-static
    --disable-static
    --with-zlib-dir
    --without-zlib-dir
    --with-zlib-include
    --without-zlib-include=${zlib-dir}/include
    --with-zlib-lib
    --without-zlib-lib=${zlib-dir}/lib
    --enable-cross-build
    --disable-cross-build

extconf failed, exit code 1

Gem files will remain installed in /Users/wuxj/.rvm/gems/ruby-2.1.2/gems/nokogiri-1.6.3.1 for inspection.
Results logged to /Users/wuxj/.rvm/gems/ruby-2.1.2/extensions/x86_64-darwin-13/2.1.0-static/nokogiri-1.6.3.1/gem_make.out
An error occurred while installing nokogiri (1.6.3.1), and Bundler cannot continue.
Make sure that `gem install nokogiri -v ‘1.6.3.1‘` succeeds before bundling.

WutekiMacBook-Pro:sample_app wuxj$ gem install nokogiri
Building native extensions.  This could take a while...
Building nokogiri using packaged libraries.
ERROR:  Error installing nokogiri:
    ERROR: Failed to build gem native extension.

    /Users/wuxj/.rvm/rubies/ruby-2.1.2/bin/ruby -r ./siteconf20140830-1261-1vvz386.rb extconf.rb
Building nokogiri using packaged libraries.
-----
libiconv is missing.  please visit http://nokogiri.org/tutorials/installing_nokogiri.html for help with installing dependencies.
-----
*** 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/wuxj/.rvm/rubies/ruby-2.1.2/bin/ruby
    --help
    --clean
    --use-system-libraries
    --enable-static
    --disable-static
    --with-zlib-dir
    --without-zlib-dir
    --with-zlib-include
    --without-zlib-include=${zlib-dir}/include
    --with-zlib-lib
    --without-zlib-lib=${zlib-dir}/lib
    --enable-cross-build
    --disable-cross-build

extconf failed, exit code 1

Gem files will remain installed in /Users/wuxj/.rvm/gems/ruby-2.1.2/gems/nokogiri-1.6.3.1 for inspection.
Results logged to /Users/wuxj/.rvm/gems/ruby-2.1.2/extensions/x86_64-darwin-13/2.1.0-static/nokogiri-1.6.3.1/gem_make.out

brew install autoconf
brew install automake
brew install libtool
brew install ap
ple-gcc42
brew install libyaml
brew install libxslt
brew install libksba
brew install openssl

WutekiMacBook-Pro:sample_app wuxj$ rvm requirements
Checking requirements for osx.
Updating certificates in ‘/usr/local/etc/openssl/cert.pem‘.
Requirements installation successful.