安装jekyll出错 Failed to build gem native extension.

============================================================博文原创，转载请声明出处电子咖啡-专注于移动互联网
============================================================

安装jekyll出错
环境Xcode 5.1and OS X 10.9
command-line Tools已是最新

Building native extensions. This could take a while...
ERROR: Error installing jekyll:
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 porter.c
porter.c:359:27: warning: '&&' within '||' [-Wlogical-op-parentheses]
if (a > 1 || a == 1 && !cvc(z, z->k - 1)) z->k--;
~~ ~~~~~~~^~~~~~~~~~~~~~~~~~~~
porter.c:359:27: note: place parentheses around the '&&' expression to silence this warning
if (a > 1 || a == 1 && !cvc(z, z->k - 1)) z->k--;
^
( )
1 warning generated.
compiling porter_wrap.c
linking shared-object stemmer.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: *** [stemmer.bundle] Error 1

Gem files will remain installed in /Library/Ruby/Gems/2.0.0/gems/fast-stemmer-1.0.2 for inspection.
Results logged to /Library/Ruby/Gems/2.0.0/gems/fast-stemmer-1.0.2/ext/gem_make.out

原因：
ruby是2.0，版本低
解决方法，
1、安装rvm
2、更新ruby到2.1
3、重新安装gem install jekyll
参考：
http://www.soimort.org/posts/101/

https://github.com/jekyll/jekyll/issues/2125#issuecomment-37373112