On the Mac, SuperCollider (SC) extensions go in the directory
~/Library/Application Support/SuperCollider/Extensionsinstead of /share/SuperCollider/Extensions as on Linux. Again it is nice to organize all Faust-generated plugins in a Faust subdirectory of Extensions.
For a nice collection of example SC plugins, see https://github.com/supercollider/example-plugins
Since pre-built versions of SC for the Mac do not seem to include the headers for compiling plugins, you probably need also to download the SC source and set the SUPERCOLLIDER_HEADERS environment variable to point into it. For example, at the time of this writing, the latest stable SC source is v3.4.4, so I have
setenv SUPERCOLLIDER_HEADERS $HOME/sc-3.4.4/common/Headersin my .tcshrc file. For Bourne shell (bash) users, add the lines
SUPERCOLLIDER_HEADERS=$HOME/sc-3.4.4/common/Headers export SUPERCOLLIDER_HEADERSin /.bashrc, etc.
To create a 32-bit plugin instead of the default 64-bit case, copy the faust2supercollider script and add ``-m32'' at the end of the SCFLAGS variable to get
SCFLAGS="-DNO_LIBSNDFILE -DSC_DARWIN -bundle -m32"
One difference on the Mac relative to Linux is that the mouse-controlled example of the previous section has its vertical axis flipped. That is, on the Mac, the volume gets louder as the mouse goes down on the screen.
If either of the above FaustOsc examples does not work on either Linux or the Mac, try checking out the latest git FAUST distribution, as described in §1.1. This document is updated to stay in sync with that (latest) version, as opposed to any particular prior FAUST release.
For some SuperCollider doc on making FAUST UGens, see https://doc.sccode.org/Guides/WritingUGens.html#FAUST.