Ray

在終端機輸入：sudo gem install sass

出現錯誤訊息時：

Building native extensions.  This could take a while...

ERROR:  Error installing sass:

ERROR: Failed to build gem native extension.

    current directory: /usr/local/lib/ruby/gems/2.4.0/gems/ffi-1.9.18/ext/ffi_c

/usr/local/opt/ruby/bin/ruby -r ./siteconf20180117-19768-w1uyn4.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

--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=/usr/local/Cellar/ruby/2.4.1_2/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

/usr/local/Cellar/ruby/2.4.1_2/lib/ruby/2.4.0/mkmf.rb:457:in `try_do': The compiler failed to generate an executable file. (RuntimeError)

You have to install development tools first.

from /usr/local/Cellar/ruby/2.4.1_2/lib/ruby/2.4.0/mkmf.rb:588:in `try_cpp'

from /usr/local/Cellar/ruby/2.4.1_2/lib/ruby/2.4.0/mkmf.rb:1095:in `block in have_header'

from /usr/local/Cellar/ruby/2.4.1_2/lib/ruby/2.4.0/mkmf.rb:945:in `block in checking_for'

from /usr/local/Cellar/ruby/2.4.1_2/lib/ruby/2.4.0/mkmf.rb:351:in `block (2 levels) in postpone'

from /usr/local/Cellar/ruby/2.4.1_2/lib/ruby/2.4.0/mkmf.rb:321:in `open'

from /usr/local/Cellar/ruby/2.4.1_2/lib/ruby/2.4.0/mkmf.rb:351:in `block in postpone'

from /usr/local/Cellar/ruby/2.4.1_2/lib/ruby/2.4.0/mkmf.rb:321:in `open'

from /usr/local/Cellar/ruby/2.4.1_2/lib/ruby/2.4.0/mkmf.rb:347:in `postpone'

from /usr/local/Cellar/ruby/2.4.1_2/lib/ruby/2.4.0/mkmf.rb:944:in `checking_for'

from /usr/local/Cellar/ruby/2.4.1_2/lib/ruby/2.4.0/mkmf.rb:1094: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:

  /usr/local/lib/ruby/gems/2.4.0/extensions/x86_64-darwin-16/2.4.0/ffi-1.9.18/mkmf.log

extconf failed, exit code 1

Gem files will remain installed in /usr/local/lib/ruby/gems/2.4.0/gems/ffi-1.9.18 for inspection.

Results logged to /usr/local/lib/ruby/gems/2.4.0/extensions/x86_64-darwin-16/2.4.0/ffi-1.9.18/gem_make.out

解決方法：於終端機輸入 xcode-select --install

即可再安裝一次sass