Error: /usr/include/php5/ext/pcre/php_pcre.h:29:18: error: pcre.h: No such file or directory
I didn't have the header files for pcre installed - in ubuntu the headers are in the -dev packages so I just installed what I needed:
sudo aptitude install libpcre3-dev
Re-attempting the pecl install, everything worked as expected. This is on Ubuntu 10.04 Lucid Lynx, and from reading around you'd want to install the same package in response to this error message, regardless of what you were doing to cause it. Hope this helps someone.