I am trying to locate or build a heroku buildpack that supports the php imap functions such as imap_open() Do I really need to recompile php and then store the binary on amazon?
The current buildpack I am using is https://github.com/Americastestkitchen/heroku-wordpress-php.git
First try the Winglian Buildpack, a dramatically improved fork of the standard PHP buildpack (the standard PHP buildpack has a single blocking worker thread and does not even use Heroku's own vulcan build system to compile binaries). If that buildpack doesn't have imap installed yet, then at the very least it will be much easier to fork and improve it than to fork and improve the default buildpack.
There are other buildpacks on github, some of which may have imap already, but few of which are as professional as Winglian's.
I needed this feature as well, so I forked the Winglian Buildpack, added imap support and cleaned some things up. The buildpack is available here, feel free to try it out ;) https://github.com/mattiasottosson/heroku-buildpack-php
Demo app just showing php-config: php-imap.herokuapp.com
Well it turns out that yes you do need to recompile the binaries for custom extensions to php such as imap, sometimes there are no shortcuts!