add custom js to the certain input element on the checkout page

sudo yum install libicu
sudo yum install libicu-devel.x86_64
sudo /usr/bin/pecl install intl
sudo echo 'extension=intl.so' >> /etc/php.ini

And you are good to go. And better enter the extension=intl.so manually to php.ini or even more elegant create a new .ini file in the /etc/php.d/ directory.

You are correct, you can't install the PECL package because as of PHP 5.3 Intl is part of PHP.

If you installed PHP using YUM, you can just pull down the intl package:

> yum list php*intl
> yum install <file_from_above>

As I don't really understand why you should need a width of 2cm;, I propose a very simple solution based on the makecell package, and its \thead command, that allows for line breaks in cells and a common formatting of cells. Does this code produce what you want?

\documentclass{article}
\usepackage{makecell}
\renewcommand\theadfont{\bfseries}

\usepackage{array}

\begin{document}

\begin{table}[htbp]
\centering
\begin{tabular}{l c c c c}
& \multicolumn{2}{c}{\thead{Some Big\\ Words}} & \multicolumn{2}{c}{\thead{More Big\\ Words}} \\
rowname & BlahBlah & BlahBlah & BlahBlah & BlahBlah
\end{tabular}
\end{table}

\end{document}