title: How to Install Rails on MAC: Error Installing Rails on MAC
body: <p>I am trying to set Rails on my MAC, but continue to get an error even with all the previous help provided by people that have also faced the same problem.</p>
  
  <p>I downloaded Ruby 2.4.1 using rbenv and now I need to install rails 4.2.1 but I continue to get the following error. </p>
  
  <p>ERROR:  Error installing rails:
      ERROR: Failed to build gem native extension.</p>
  
  <pre><code>Fetching actionview-4.2.1.gem
  Fetching actionpack-4.2.1.gem
  Fetching railties-4.2.1.gem
  Fetching activejob-4.2.1.gem
  Fetching actionmailer-4.2.1.gem
  Fetching activemodel-4.2.1.gem
  Fetching activerecord-4.2.1.gem
  Fetching rails-4.2.1.gem
  Building native extensions. This could take a while...
  ERROR:  Error installing rails:
      ERROR: Failed to build gem native extension.
  
      current directory: /Library/Ruby/Gems/2.3.0/gems/nokogiri-1.10.3/ext/nokogiri
  /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/bin/ruby -I /Library/Ruby/Site/2.3.0 -r ./siteconf20190527-36261-6oqyvd.rb extconf.rb
  checking if the C compiler accepts  -I     /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/libxml2... yes
  checking if the C compiler accepts -Wno-error=unused-command-line-argument-hard-error-in-future... no
  Building nokogiri using packaged libraries.
  Using mini_portile version 2.4.0
  checking for iconv.h... yes
  checking for gzdopen() in -lz... yes
  checking for iconv... yes
  ************************************************************************
  IMPORTANT NOTICE:
  
  Building Nokogiri with a packaged version of libxml2-2.9.9
  with the following patches applied:
      - 0001-Revert-Do-not-URI-escape-in-server-side-includes.patch
      - 0002-Remove-script-macro-support.patch
      - 0003-Update-entities-to-remove-handling-of-ssi.patch
  
  Team Nokogiri will keep on doing their best to provide security updates in a timely manner, but if this is a concern for you and want to use the system library instead; abort this installation process and reinstall nokogiri as follows:
  
      gem install nokogiri -- --use-system-libraries
          [--with-xml2-config=/path/to/xml2-config]
          [--with-xslt-config=/path/to/xslt-config]
  
  If you are using Bundler, tell it to use the option:
  
      bundle config build.nokogiri --use-system-libraries
      bundle install
  
  Note, however, that nokogiri is not fully compatible with arbitrary versions of libxml2 provided by OS/package vendors.
  ************************************************************************
  Extracting libxml2-2.9.9.tar.gz into tmp/x86_64-apple-darwin17/ports/libxml2/2.9.9... OK
  Running git apply with /Library/Ruby/Gems/2.3.0/gems/nokogiri-1.10.3/patches/libxml2/0001-Revert-Do-not-URI-escape-in-server-side-includes.patch... OK
  Running git apply with /Library/Ruby/Gems/2.3.0/gems/nokogiri-1.10.3/patches/libxml2/0002-Remove-script-macro-support.patch... OK
  Running git apply with /Library/Ruby/Gems/2.3.0/gems/nokogiri-1.10.3/patches/libxml2/0003-Update-entities-to-remove-handling-of-ssi.patch... OK
  Running 'configure' for libxml2 2.9.9... OK
  Running 'compile' for libxml2 2.9.9... ERROR, review '/Library/Ruby/Gems/2.3.0/gems/nokogiri-1.10.3/ext/nokogiri/tmp/x86_64 apple-darwin17/ports/libxml2/2.9.9/compile.log' to see what happened. Last lines are:
  ========================================================================
    CC       testdso.lo
    CCLD     testdso.la
    CC       xmllint.o
    CCLD     xmllint
  ld: warning: The i386 architecture is deprecated for macOS (remove from the Xcode build setting: ARCHS)
  ld: warning: ignoring file /usr/local/Cellar/xz/5.2.4/lib/liblzma.dylib, file was built for x86_64 which is not the architecture being linked (i386): /usr/local/Cellar/xz/5.2.4/lib/liblzma.dylib
  Undefined symbols for architecture i386:
    "_lzma_auto_decoder", referenced from:
        _xz_head in libxml2.a(xzlib.o)
    "_lzma_code", referenced from:
        _xz_decomp in libxml2.a(xzlib.o)
    "_lzma_end", referenced from:
        ___libxml2_xzclose in libxml2.a(xzlib.o)
    "_lzma_properties_decode", referenced from:
        _is_format_lzma in libxml2.a(xzlib.o)
  ld: symbol(s) not found for architecture i386
  clang: error: linker command failed with exit code 1 (use -v to see invocation)
  make[2]: *** [xmllint] Error 1
  make[1]: *** [all-recursive] Error 1
  make: *** [all] Error 2
  ========================================================================
  *** 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=/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/bin/$(RUBY_BASE_NAME)
      --help
      --clean
      --use-system-libraries
      --enable-static
      --disable-static
      --with-zlib-dir
      --without-zlib-dir
      --with-zlib-include
      --without-zlib-include=${zlib-dir}/include
      --with-zlib-lib
      --without-zlib-lib=${zlib-dir}/lib
      --enable-cross-build
      --disable-cross-build
  /Library/Ruby/Gems/2.3.0/gems/mini_portile2-2.4.0/lib/mini_portile2/mini_portile.rb:402:in `block in execute': Failed to complete compile task (RuntimeError)
  from /Library/Ruby/Gems/2.3.0/gems/mini_portile2-2.4.0/lib/mini_portile2/mini_portile.rb:373:in `chdir'
  from /Library/Ruby/Gems/2.3.0/gems/mini_portile2-2.4.0/lib/mini_portile2/mini_portile.rb:373:in `execute'
  from /Library/Ruby/Gems/2.3.0/gems/mini_portile2-2.4.0/lib/mini_portile2/mini_portile.rb:115:in `compile'
  from /Library/Ruby/Gems/2.3.0/gems/mini_portile2-2.4.0/lib/mini_portile2/mini_portile.rb:154:in `cook'
  from extconf.rb:365:in `block (2 levels) in process_recipe'
  from extconf.rb:257:in `block in chdir_for_build'
  from extconf.rb:256:in `chdir'
  from extconf.rb:256:in `chdir_for_build'
  from extconf.rb:364:in `block in process_recipe'
  from extconf.rb:262:in `tap'
  from extconf.rb:262:in `process_recipe'
  from extconf.rb:557:in `&lt;main&gt;'
  
  To see why this extension failed to compile, please check the mkmf.log which can be found here:
  
    /Library/Ruby/Gems/2.3.0/extensions/universal-darwin-17/2.3.0/nokogiri-1.10.3/mkmf.log
  
  extconf failed, exit code 1
  
  Gem files will remain installed in /Library/Ruby/Gems/2.3.0/gems/nokogiri-1.10.3 for inspection.
  Results logged to /Library/Ruby/Gems/2.3.0/extensions/universal-darwin-17/2.3.0/nokogiri-1.10.3/gem_make.out
  </code></pre>
  
  <p>I have seen:</p>
  
  <pre><code>gem update --system 3.0.3
  </code></pre>
  
  <p>But don't need this as I already have the latest version of gem.</p>
  
  <p>I have tried:</p>
  
  <pre><code>sudo gem install rails --version 4.2.1
  </code></pre>
  
  <p>But this is what throws the above error.</p>