解决 Mac OS 10.14: Failed to build

环境

Mac OS Mojave 10.14
ruby 2.3.7p456 (2018-03-28 revision 63024)

报错信息:

$ sudo gem install sass
Building native extensions. This could take a while...
ERROR:  Error installing sass:
    ERROR: Failed to build gem native extension.

    current directory: /Library/Ruby/Gems/2.3.0/gems/ffi-1.11.1/ext/ffi_c
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/bin/ruby -I /Library/Ruby/Site/2.3.0 -r ./siteconf20191022-2775-1q9uxye.rb extconf.rb
mkmf.rb can't find header files for ruby at /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/include/ruby.h

extconf failed, exit code 1

Gem files will remain installed in /Library/Ruby/Gems/2.3.0/gems/ffi-1.11.1 for inspection.
Results logged to /Library/Ruby/Gems/2.3.0/extensions/universal-darwin-18/2.3.0/ffi-1.11.1/gem_make.out

解决方法：

如果是之前的 Mac OS 版本，网上都是通过 xcode-select --install 来解决，但是我在 Mac OS 10.14 版本下，依然存在报错。

最终找到解决方式，执行：

open /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg

然后根据提示安装即可。