According to Maelstorm himself, a "make" is enough to make his object.
Download the .zip file and open a terminal (Applications -> Utilities -> Terminal.app). In there type "cd " (space included) and drag and drop the folder of the object (the one that is unzipped), and hit enter. Then type "make" and hit enter again. If everything is already sorted out by the developer, the object should compile without a problem. If it doesn't compile, come back here and post the error messages that appear in the terminal.

Hi Alexandro, and thanks for your advice. I tried what you suggested and initially got this error message:

/bin/sh: cc: command not found
make: *** [vphasor~.o] Error 127

I deleted the folder, unzipped and re-do your instructions and still got the same.

Should I end up with a .pd_darwin file?

I think you're missing the command line tools which are provided by XCode. Can't remember how to install them, but having XCode installed (which you probably should?), google how to install the included command line tools.
Once you have these tools, "make" will be recognized and will actually try to make the binary.
Eventually you should end up with either a .pd_darwin or a .d_fat binary, not sure which of the two.

I haven't used Mac in a while, but you should be able to install the command line tools without installing all of XCode.

Yeah you can, I downloaded command line tools for my OS X (10.8.5) from the Developer Downloads area. However I still got this error after "make":

cc -I"/Applications/Pd-extended.app/Contents/Resources/include/pd" -DPD -DVERSION='"0.0"' -arch ppc -arch i386 -arch x86_64 -mmacosx-version-min=10.4 -fPIC -I/sw/include -Wall -W -g -ftree-vectorize -ftree-vectorizer-verbose=2 -fast -o "vphasor~.o" -c "vphasor~.c"
clang: error: unknown argument: '-ftree-vectorizer-verbose=2' [-Wunused-command-line-argument-hard-error-in-future]
clang: note: this will be a hard error (cannot be downgraded to a warning) in the future
make: *** [vphasor~.o] Error 1

I'm gonna go ahead and install xCode 5.1 and then try installing command line tools again from there.

Cheers.

@sergio maybe you should start a new thread about this, cause we've deviated from the original subject quite a lot, and now we're hijacking this thread..

So excited to see the browser to find externals into the app!