diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index a49f37ab..463f9b03 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -23,13 +23,26 @@ if(WITH_XKB)
 endif()
 
 add_subdirectory(xpp)
+if (NOT TARGET xpp)
+  message(FATAL_ERROR "Target xpp not generated")
+else()
+  get_target_property(_xpp_includes xpp INCLUDE_DIRECTORIES)
+  set_target_properties(xpp PROPERTIES INCLUDE_DIRECTORIES "")
+  target_include_directories(xpp SYSTEM PUBLIC ${_xpp_includes})
+endif()
 
 # }}}
 # Library: i3ipcpp {{{
 
 if(ENABLE_I3)
   add_subdirectory(i3ipcpp)
-  list(APPEND libs ${I3IPCPP_LIBRARIES})
+  if (NOT TARGET i3ipc++)
+    message(FATAL_ERROR "Target i3ipcpp not generated")
+  else()
+    get_target_property(_i3ipcpp_includes i3ipc++ INCLUDE_DIRECTORIES)
+    set_target_properties(i3ipc++ PROPERTIES INCLUDE_DIRECTORIES "")
+    target_include_directories(i3ipc++ SYSTEM PUBLIC ${_i3ipcpp_includes})
+  endif()
 endif()
 
 # }}}