I think, you already did. The PCLINK feature should be in R3. The OSX version, I downloaded from the Github page (your build, I think), clearly states, that it ignores the PCLINK commands.
This indicates, that RespeQt R3 knows of PCLINK.
Well I don't know then; like I said, I don't use PCLINK so I don't know why it does or doesn't work on any specific platforms. I just download and build the code.
Speaking of, here's how I do it. This presumes you have both Qt Creator and OS X/macOS Xcode installed:
1. Download the RespeQt source code and stick it where you want. I use the Desktop 2. Open respeqt.pro in Qt Creator 3. Configure the project in the opening dialogue if this is the first time you've built it; otherwise go to Step 4. 4. On the Build menu, click Build project "respeqt" 5. Once the build is complete open a Terminal window and navigate to the Qt directory. In my case it's my home directory, so cd ~/Qt-static 6. Navigate to the directory that contains the deployment tool: cd 5.5/clang_64/bin/ 5. Now you have to know the path to the application bundle you built in step 4. Once you know that, you need that path for the deployment tool. So, run the tool as follows: ./macdeployqt ~/Desktop/build-respeqt-Desktop_Qt_5_5_0_clang_64bit-Debug/RespeQt.app 6. That'll take a minute or two depending on the speed of your system, but suddenly your 1.7 megabyte app balloons to 25+ megabytes, and voila. You should have a portable app that carries the OS X frameworks with it necessary to use the app on Macs without the Qt libraries installed. 7. Manually copy every folder which begins with a $ character from the source directory into the application bundle and voila. Done.
I haven't figured out how to deploy the app from within Qt Creator and the documentation sucks, so the Terminal commands are how I do it. Similarly, I don't know enough about Qt or C++ coding to have the OS X branch copy those folders into into the application bundle (step 7 above), but copying them manually works.
Further discussion should probably be in the RespeQt forum.