diff --git a/gdk/Makefile.am b/gdk/Makefile.am
index eb6672197f..dcaeb148f5 100644
--- a/gdk/Makefile.am
+++ b/gdk/Makefile.am
@@ -3,7 +3,8 @@ include $(top_srcdir)/Makefile.decl
 -include $(INTROSPECTION_MAKEFILE)
 INTROSPECTION_GIRS =
 INTROSPECTION_SCANNER_ARGS = \
-   --add-include-path=../gdk
+	--add-include-path=../gdk \
+	--warn-all
 INTROSPECTION_COMPILER_ARGS = \
    --includedir=$(srcdir) \
    --includedir=.
diff --git a/gtk/Makefile.am b/gtk/Makefile.am
index fc3a86a06f..78957d30da 100644
--- a/gtk/Makefile.am
+++ b/gtk/Makefile.am
@@ -3,7 +3,8 @@ include $(top_srcdir)/Makefile.decl
 -include $(INTROSPECTION_MAKEFILE)
 INTROSPECTION_GIRS =
 INTROSPECTION_SCANNER_ARGS = \
-	--add-include-path=../gdk
+	--add-include-path=../gdk \
+	--warn-all
 INTROSPECTION_COMPILER_ARGS = \
 	--includedir=$(srcdir) \
     --includedir=. \