So I installed it via macports:
sudo port install gd2unfortunately ./configure continued to complain. Finally today a solution for how to run ./configure was posted on the Erlang mailing list:
./configure --with-gd=/opt/localand everything went without further problems ...
There a lots of new features and improvements, and I look forward to explore them one by one in the next weeks and months. Just the troublemaker percept I had to inspect immediately. It seems to be a powerful tool for performance analysis and it ships with a module called edg which wraps libgd and serves for creating 2D vector graphics (to visualize the percept profiling results), similar to my own erlycairo, but it produces*.gif files (erlycairo only outputs *.png files).