无法安装mysql gem / ruby​​-dev

Question

我正在尝试安装ruby mysql gem。 gem install mysql我得到：

Building native extensions.  This could take a while...
ERROR:  Error installing mysql:
ERROR: Failed to build gem native extension.

    /usr/bin/ruby1.9.1 extconf.rb
/usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require': cannot load such file -- mkmf (LoadError)
from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
from extconf.rb:5:in `<main>'


Gem files will remain installed in /var/lib/gems/1.9.1/gems/mysql-2.9.1 for inspection.
Results logged to /var/lib/gems/1.9.1/gems/mysql-2.9.1/ext/mysql_api/gem_make.out

我找到了建议安装ruby-dev 答案 ，但是在apt-get install ruby1.9.1-dev或apt-get install ruby-dev我得到了：

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
ruby1.9.1-dev : Depends: libruby1.9.1 (= 1.9.3.194-8.1ubuntu2) but 1.9.3.194-8.1ubuntu2.1 is to be installed
                Recommends: ruby1.9.1 (= 1.9.3.194-8.1ubuntu2) but 1.9.3.194-8.1ubuntu2.1 is to be installed
E: Unable to correct problems, you have held broken packages.

1）如何解决此问题？

2）更有趣的是：由于问题是在全新的xubuntu安装上发生的，导致这种类型错误的原因是什么？ 我是否在不知不觉中打破了某些东西？ 我将欣赏指向资源的链接，该链接将帮助我了解Linux下Ubuntu软件包管理器的方式和依赖项。

Answer 1

我在Ubuntu 14.04上遇到了同样的问题。 我删除所有的ruby，ruby-1.9，ruby-dev软件包，然后重新安装ruby和ruby-dev。 看来我现在可以通过gem安装ruby软件了。