下記がError文になります。  
sudo gem install compass -n /usr/local/bin/  
上記等色々試したのですがインストール出来ず。。。  
ご教授頂けると幸いです。

======================================================================

```

    MacBook-Pro:~ WEB20-150129$ sudo gem install compass
    Password:
    Building native extensions. This could take a while...
    ERROR:  Error installing compass:
        ERROR: Failed to build gem native extension.
    
        current directory: /Library/Ruby/Gems/2.3.0/gems/ffi-1.9.25/ext/ffi_c
    /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/bin/ruby -r ./siteconf20180929-7168-fcft1p.rb extconf.rb
    checking for ffi.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
        --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/$(RUBY_BASE_NAME)
        --with-ffi_c-dir
        --without-ffi_c-dir
        --with-ffi_c-include
        --without-ffi_c-include=${ffi_c-dir}/include
        --with-ffi_c-lib
        --without-ffi_c-lib=${ffi_c-dir}/lib
        --with-libffi-config
        --without-libffi-config
        --with-pkg-config
        --without-pkg-config
    /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/mkmf.rb:456:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
    You have to install development tools first.
        from /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/mkmf.rb:571:in `block in try_compile'
        from /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/mkmf.rb:524:in `with_werror'
        from /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/mkmf.rb:571:in `try_compile'
        from /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/mkmf.rb:1091:in `block in have_header'
        from /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/mkmf.rb:942:in `block in checking_for'
        from /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/mkmf.rb:350:in `block (2 levels) in postpone'
        from /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/mkmf.rb:320:in `open'
        from /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/mkmf.rb:350:in `block in postpone'
        from /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/mkmf.rb:320:in `open'
        from /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/mkmf.rb:346:in `postpone'
        from /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/mkmf.rb:941:in `checking_for'
        from /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/mkmf.rb:1090:in `have_header'
        from extconf.rb:16:in `<main>'
    
    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-18/2.3.0/ffi-1.9.25/mkmf.log
    
    extconf failed, exit code 1
    
    Gem files will remain installed in /Library/Ruby/Gems/2.3.0/gems/ffi-1.9.25 for inspection.
    Results logged to /Library/Ruby/Gems/2.3.0/extensions/universal-darwin-18/2.3.0/ffi-1.9.25/gem_make.out
    
```

======================================================================
CC BY-SA 4.0
2018-09-28T19:52:28.977
48802
2018-09-28T22:23:57.703
2018-09-28T22:23:57.703
19769
30276
question
sass
macでcompassを入れようとしたらErrorでハマってしまいました、、助けて頂けると幸いです。