I’ve finally found the solution. Most of it was here:http://www.september28.co.uk/blog/2011/11/24/php-imap-support-in-mac-os-x-lion-without-recompiling-php/
My machine is a late 2011 Macbook Pro with MacOSX 10.7.4, PHP 5.4. installed via these instructions: http://www.hirmet.com/mac-os-x-lion-upgrade-to-php-5-4
Here’s a step-by-step for those with a similar or identical setup:
Download the imap source from this url, focus on the one with the most recent date which doesn’t end in “Z”: ftp://ftp.cac.washington.edu/imap/
Unarchive, go into folder, run the following commands:
The above command will throw a bunch of warnings at you, but should complete sucessfully, unlike the command originally suggested in the september28 blog post.
Next, do the following:
Once this is done, go into the downloaded php source folder if you made a custom upgrade like I did (as per the second link in the answer) and build the imap.so extension for your system. If you didn’t build a custom version, just download the PHP source for the version you have installed, and use that, it doesn’t matter.
Once done, do the following:
…or if your PHP extension folder is different, put that (you can see the location in phpinfo(); )
Restart apache and you should be ready to go.