Fix build with old cmake

Closes #407

Signed-off-by: falkTX <falktx@falktx.com>

cmake/DPF-plugin.cmake

@@ -231,7 +231,7 @@ function(dpf__build_jack NAME HAS_UI)
     target_compile_definitions("${NAME}" PUBLIC "HAVE_SDL2")
     target_include_directories("${NAME}-jack" PRIVATE ${SDL2_STATIC_INCLUDE_DIRS})
     target_link_libraries("${NAME}-jack" PRIVATE ${SDL2_STATIC_LIBRARIES})
-    dpf__target_link_directories("${NAME}-jack" ${SDL2_STATIC_LIBRARY_DIRS})
+    dpf__target_link_directories("${NAME}-jack" "${SDL2_STATIC_LIBRARY_DIRS}")
   endif()
 
   if(APPLE OR WIN32)
@@ -244,13 +244,13 @@ function(dpf__build_jack NAME HAS_UI)
       target_compile_definitions("${NAME}" PUBLIC "HAVE_ALSA")
       target_include_directories("${NAME}-jack" PRIVATE ${ALSA_INCLUDE_DIRS})
       target_link_libraries("${NAME}-jack" PRIVATE ${ALSA_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT})
-      dpf__target_link_directories("${NAME}-jack" ${ALSA_LIBRARY_DIRS})
+      dpf__target_link_directories("${NAME}-jack" "${ALSA_LIBRARY_DIRS}")
     endif()
     if(PULSEAUDIO_FOUND)
       target_compile_definitions("${NAME}" PUBLIC "HAVE_PULSEAUDIO")
       target_include_directories("${NAME}-jack" PRIVATE ${PULSEAUDIO_INCLUDE_DIRS})
       target_link_libraries("${NAME}-jack" PRIVATE ${PULSEAUDIO_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT})
-      dpf__target_link_directories("${NAME}-jack" ${PULSEAUDIO_LIBRARY_DIRS})
+      dpf__target_link_directories("${NAME}-jack" "${PULSEAUDIO_LIBRARY_DIRS}")
     endif()
     if(ALSA_FOUND OR PULSEAUDIO_FOUND)
       target_compile_definitions("${NAME}" PUBLIC "HAVE_RTAUDIO")
@@ -330,7 +330,7 @@ function(dpf__build_dssi NAME HAS_UI)
     target_compile_definitions("${NAME}" PUBLIC "HAVE_LIBLO")
     target_include_directories("${NAME}-dssi-ui" PRIVATE ${LIBLO_INCLUDE_DIRS})
     target_link_libraries("${NAME}-dssi-ui" PRIVATE ${LIBLO_LIBRARIES})
-    dpf__target_link_directories("${NAME}-dssi-ui" ${LIBLO_LIBRARY_DIRS})
+    dpf__target_link_directories("${NAME}-dssi-ui" "${LIBLO_LIBRARY_DIRS}")
   endif()
 endfunction()