错误：安装 gollum 时出错：错误：无法构建 gem 本机扩展

我无法安装gollum-wiki全新安装后ruby v2.2.2 via rbenv.

I run Ubuntu-Gnome 14.04 Trusty Thar.

这是安装日志：

user@host:~/dev/drafts$ gem install gollum
Fetching: useragent-0.10.0.gem (100%)
Successfully installed useragent-0.10.0
Fetching: mustache-0.99.8.gem (100%)
Successfully installed mustache-0.99.8
Fetching: rack-1.6.4.gem (100%)
Successfully installed rack-1.6.4
Fetching: rack-protection-1.5.3.gem (100%)
Successfully installed rack-protection-1.5.3
Fetching: tilt-2.0.1.gem (100%)
Successfully installed tilt-2.0.1
Fetching: sinatra-1.4.6.gem (100%)
Successfully installed sinatra-1.4.6
Fetching: kramdown-1.6.0.gem (100%)
Successfully installed kramdown-1.6.0
Fetching: github-markup-1.3.3.gem (100%)
Successfully installed github-markup-1.3.3
Fetching: mini_portile-0.6.2.gem (100%)
Successfully installed mini_portile-0.6.2
Fetching: nokogiri-1.6.6.2.gem (100%)
Building native extensions.  This could take a while...
Successfully installed nokogiri-1.6.6.2
Fetching: sanitize-2.1.0.gem (100%)
Successfully installed sanitize-2.1.0
Fetching: stringex-2.5.2.gem (100%)
Successfully installed stringex-2.5.2
Fetching: rouge-1.9.1.gem (100%)
Successfully installed rouge-1.9.1
Fetching: diff-lcs-1.2.5.gem (100%)
Successfully installed diff-lcs-1.2.5
Fetching: mime-types-1.25.1.gem (100%)
Successfully installed mime-types-1.25.1
Fetching: posix-spawn-0.3.11.gem (100%)
Building native extensions.  This could take a while...
Successfully installed posix-spawn-0.3.11
Fetching: charlock_holmes-0.7.3.gem (100%)
Building native extensions.  This could take a while...
ERROR:  Error installing gollum:
        ERROR: Failed to build gem native extension.

    /home/poremil/.rbenv/versions/2.2.2/bin/ruby -r ./siteconf20150818-19908-1246gx8.rb extconf.rb
checking for main() in -licui18n... no
checking for main() in -licui18n... no


***************************************************************************************
*********** icu required (brew install icu4c or apt-get install libicu-dev) ***********
***************************************************************************************
*** 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
        --without-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=/home/poremil/.rbenv/versions/2.2.2/bin/$(RUBY_BASE_NAME)
        --with-icu-dir
        --without-icu-dir
        --with-icu-include
        --without-icu-include=${icu-dir}/include
        --with-icu-lib
        --without-icu-lib=${icu-dir}/lib
        --with-icui18nlib
        --without-icui18nlib
        --with-icui18nlib
        --without-icui18nlib

extconf failed, exit code 1

Gem files will remain installed in /home/poremil/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/charlock_holmes-0.7.3 for inspection.
Results logged to /home/poremil/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/extensions/x86_64-linux/2.2.0-static/charlock_holmes-0.7.3/gem_make.out

只需安装即可libicu-dev via apt

$ sudo apt-get install libicu-dev

然后安装gollum

$ gem install gollum