Whoocus

bundle install が、nokogiri のライブラリ依存で失敗した場合。

Installing nokogiri 1.6.8.1 with native extensions
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

    current directory: /Users/xxxxx/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/nokogiri-1.6.8.1/ext/nokogiri
/Users/xxxxx/.rbenv/versions/2.3.1/bin/ruby -r ./siteconf20161206-45292-57wgxr.rb extconf.rb
checking if the C compiler accepts ... yes
checking if the C compiler accepts -Wno-error=unused-command-line-argument-hard-error-in-future... no
Building nokogiri using packaged libraries.
Using mini_portile version 2.1.0
checking for iconv.h... yes
checking for gzdopen() in -lz... yes
checking for iconv... yes
************************************************************************
IMPORTANT NOTICE:

Building Nokogiri with a packaged version of libxml2-2.9.4.

Team Nokogiri will keep on doing their best to provide security
updates in a timely manner, but if this is a concern for you and want
to use the system library instead; abort this installation process and
reinstall nokogiri as follows:

    gem install nokogiri -- --use-system-libraries
        [--with-xml2-config=/path/to/xml2-config]
        [--with-xslt-config=/path/to/xslt-config]

If you are using Bundler, tell it to use the option:

    bundle config build.nokogiri --use-system-libraries
    bundle install

Note, however, that nokogiri is not fully compatible with arbitrary
versions of libxml2 provided by OS/package vendors.
************************************************************************

brewで、libxml2 をインストールして、bundleのオプションで、libxml2 のライブラリの場所を指定する。

$ brew install libxml2
$ bundle config build.nokogiri --use-system-libraries --with-xml2-include=/usr/local/opt/libxml2/include/libxml2/
$ bundle install