It’s a trick i used to get the AU build to work at all. I added a special project: https://github.com/RomanKubiak/ctrlr/tree/master/Builds/AU/Wrapper
you need to build it first, it generates a static library that you need to copy somewhere (i use /usr/local/lib or /usr/lib so that the linker sees it) and the Ctrlr_AU project links to that. I had to do that, otherwise there are issues when building with precompiled headers (JUCE has problems with that). But that trick works.