Change plugin output directory behaviour between normal and super- builds

CMakeLists.txt

@@ -11,7 +11,7 @@ cmake_minimum_required(VERSION 3.11)
 # Paths
 set(CMAKE_INSTALL_PREFIX "${CMAKE_CURRENT_SOURCE_DIR}/release-packaging")
 set(MAX_TARGET_NAMESPACE "" CACHE STRING "Optional namesapce to prepend to targets to prevent collision in super-builds")
-
+set(SC_LIBRARY_OUTPUT_PREFIX "release-packaging" CACHE STRING "Where in the hierarchy to write sc plugins (different for superbuild)")
 
 set(SC_PATH "" CACHE PATH "Path to the top of SuperCollider source tree")
 if(NOT SC_PATH)
@@ -67,7 +67,7 @@ if(NOT fluid_decomposition_POPULATED)
   include(flucoma_version)
 endif()
 
-set(CMAKE_LIBRARY_OUTPUT_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/${CMAKE_SYSTEM_NAME}/plugins")
+set(CMAKE_LIBRARY_OUTPUT_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/${SC_LIBRARY_OUTPUT_PREFIX}/plugins")
 set(CMAKE_LIBRARY_OUTPUT_DIRECTORY_DEBUG "${CMAKE_LIBRARY_OUTPUT_DIRECTORY}")
 set(CMAKE_LIBRARY_OUTPUT_DIRECTORY_RELEASE "${CMAKE_LIBRARY_OUTPUT_DIRECTORY}")
 set(CMAKE_SHARED_MODULE_PREFIX "")