diff --git a/library/include/df/custom/building_handler.methods.inc b/library/include/df/custom/building_handler.methods.inc
new file mode 100644
index 000000000..c160f5470
--- /dev/null
+++ b/library/include/df/custom/building_handler.methods.inc
@@ -0,0 +1 @@
+friend struct df::world;
diff --git a/library/include/df/custom/machine_handler.methods.inc b/library/include/df/custom/machine_handler.methods.inc
new file mode 100644
index 000000000..c160f5470
--- /dev/null
+++ b/library/include/df/custom/machine_handler.methods.inc
@@ -0,0 +1 @@
+friend struct df::world;