Unable to install Ruby gem unf_ext 0.7.4 on Ubuntu

Question

I am having a hell of a time installing unf_ext 0.7.4 on Ubuntu. I've tried every form of Google searching you can possibly imagined and installed almost everything I could think of, here's what I've installed so far:

• libgmp-dev
• ruby-dev
• zlib1g-dev
• liblzma-dev
• build-essential
• build-essential patch
• libxml2
• libxslt1.1
• openssl
• libreadline6
• libreadline6-dev
• curl
• git-core
• zlib1g
• zlib1g-dev
• libssl-dev
• libyaml-dev
• libsqlite3-0
• libsqlite3-dev
• sqlite3 (found a link somewhere that said this would help?)
• libxml2-dev
• libxslt-dev
• autoconf
• libc6-dev
• ncurses-dev
• automake
• libtool
• bison

However after having all of these installed it still does not work, so I tried

• sudo apt-get update && sudo apt-get install libxml2-dev && sudo apt-get install libxslt-dev && sudo gem install unf_ext

During that I get this error:

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:
 libxml2-dev : Depends: libxml2 (= 2.9.1+dfsg1-3ubuntu4.9) but 2.9.4+dfsg1-2.2 is to be installed
E: Unable to correct problems, you have held broken packages.

However, dpkg --get-selections displays no packages on hold and all are installed. How can I successfully get this gem installed?

Answer 1

I ran into a similar issue with installing unf_ext on Ubuntu. I had to add a swapfile to my server. Once I did that I was able to install the unf_ext gem.