The following code was used with gem 0.93-3 and pd-0.43 in os x 10.7:
1) download gem binaries for os x and gem source / only source in linux.
2) Create a project in /extra just like the other projects there.
3) modify the config files as specified in “README-EXTRA.txt”
4) run ./autogen.sh
5) run ./configure –enable-fat-binary=i386 –with-pd=/path (ignore the –enable-fat-binary=i386 flag in linux, just use it in recent versions of OSX)
6) cd into the project folder (gem/extra/pix_myexternal) and run make
7) put the project folder in the path of Pd.