^ This should be fixable in the CMakeLists.txt/ FindFoo.cmake for SuperCollider. It probalby just does not appedn the SuperCollider_INCLUDE_DIR (or something simliar) to the include_directories.
Reported the bug about missing SC include in .cmake.
This is essentially an upstream bug, let them fix it: https://github.com/supercollider/sc3-plugins/issues/170
I am adding the comment to reflect this.