I ended up with the following error at make install: PHP Fatal error: Unable to start curl module in Unknown on line 0

Finding that it was a MySQL issue, he set about trying to find the issue (turned out to be a badly linked SSL library on MySQL's part). This issue is only in the MySQL binaries, though, so if you come across it you'll just need to compile MySQL by hand first, then compile PHP against it.

It seems that this is indeed a MySQL issue and there is a PHP bug (bogused) as well as a MySQL bug report for the problem. There's also a blog entry by Ilia that details a possible solution. Basically, MySQL saw it fit to link their binary distribution not against OpenSSL (which is probably available on near 100% of unixoid hosts out there), but YaSSL - of which I personally never even heard.

Apparently, the issue comes from the clashing of function names inside the packages, making for a world of troubles. For a solution, check out Ilia's blog post mentioned before.