I'm building nginx on my server and it reports GD Library is missing.

remote: checking for GD library in /usr/local/ ... not found
remote: checking for GD library in /usr/pkg/ ... not found
remote: checking for GD library in /opt/local/ ... not found

I've downloaded GD from https://bitbucket.org/pierrejoye/gd-libgd but had to install it to a different location.

How can I change where nginx looks for GD to /path/to/my/gd?