Original question: I'm having trouble installing the PHP Pecl Intl extension on my CentOs 5 machine. After installing both icu and libicu with the following commands: $ yum install icu $ yum install libicu I tried to install the Intl extension like so: $ /usr/bin/pecl install intl I selected to search for the default location for the ICU libraries and header files. It ends up crashing like this: c