Good to see that someone did it, maybe it would be nice if @afsacp tells you how to compile it with xcode so you can do it for yourself.
A reason why it does not work could be the Architecture you are using.
If @afsacp is compiling on a 64bit arch and you are using 32bit it will not work.
If this is the case he can compile it using 32bit compiler, or gives you the advice you need to build it on your system.
Hey, none of the files have a .pd_darwin extension because these are the compiled libraries for osx.
So far as i know it is not possible to convert pre compiled libraries for other machines.
If you want to use it on your machine you will need to compile it.
Installing a virtual machine with Windows maybe a solution but not a really satisfiable one.
There is not that much that needs adjustment in the makefiles so probably this little afford
is worth it and once done you can recompile it everytime if u ever need to.
i just downloaded the package and took a look,
i would say you need to write Makefiles for your OS.
I would suggest to make copys of all the "make_linux" and "INCLUDE_linux" files
in all the directories where they exist and rename it to to something like "make_osx" .
In the subdirectories like sound_modules there are INCLUDE files where you need to set
compiler flags and those stuff.
If you have the source code of pd-extended downloaded you can look at:
there is a Makefile with the needed compiler flags for almost every OS
just search the section with "mac osx".
I am not an osx guy so i can not test it
but i hope it will help you.
If i'm wrong, please correct me.