当我做＆＃34; sudo gem install rails＆＃34;这就是我得到的：
Building native extensions. This could take a while...
ERROR: Error installing rails:
ERROR: Failed to build gem native extension.
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/bin/ruby extconf.rb
creating Makefile
make "DESTDIR="
compiling generator.c
linking shared-object json/ext/generator.bundle
clang: error: unknown argument: '-multiply_definedsuppress' [-Wunused-command-line-argument-hard-error-in-future]
clang: note: this will be a hard error (cannot be downgraded to a warning) in the future
make: *** [generator.bundle] Error 1
Gem files will remain installed in /Library/Ruby/Gems/2.0.0/gems/json-1.8.1 for inspection.
Results logged to /Library/Ruby/Gems/2.0.0/gems/json-1.8.1/ext/json/ext/generator/gem_make.out
有关如何修复的想法吗？