diff --git a/repos/gems/recipes/raw/motif_wm/decorator_init.config b/repos/gems/recipes/raw/motif_wm/decorator_init.config
index c619ae141..6043f6332 100644
--- a/repos/gems/recipes/raw/motif_wm/decorator_init.config
+++ b/repos/gems/recipes/raw/motif_wm/decorator_init.config
@@ -12,6 +12,7 @@
+
diff --git a/repos/gems/recipes/raw/motif_wm/wm.config b/repos/gems/recipes/raw/motif_wm/wm.config
index cd558c071..0ec71f3c7 100644
--- a/repos/gems/recipes/raw/motif_wm/wm.config
+++ b/repos/gems/recipes/raw/motif_wm/wm.config
@@ -45,6 +45,7 @@
+
diff --git a/repos/gems/recipes/raw/themed_wm/decorator_init.config b/repos/gems/recipes/raw/themed_wm/decorator_init.config
index 418b94471..62f638919 100644
--- a/repos/gems/recipes/raw/themed_wm/decorator_init.config
+++ b/repos/gems/recipes/raw/themed_wm/decorator_init.config
@@ -14,6 +14,7 @@
+
diff --git a/repos/os/include/os/session_policy.h b/repos/os/include/os/session_policy.h
index 425e294d8..eb1659fde 100644
--- a/repos/os/include/os/session_policy.h
+++ b/repos/os/include/os/session_policy.h
@@ -15,6 +15,7 @@
#define _INCLUDE__OS__SESSION_POLICY_H_
#include
+#include
#include
#include
#include
@@ -199,6 +200,7 @@ class Genode::Session_policy : public Xml_node
try { return config.sub_node("default-policy"); }
catch (...) { }
+ warning("no policy defined for label '", label, "'");
throw No_policy_defined();
}