diff --git a/lib/Makefile.am b/lib/Makefile.am
index 4b003598..f35ed006 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -22,7 +22,7 @@ CLEANFILES			= lib.c
 
 -include $(INTROSPECTION_MAKEFILE)
 INTROSPECTION_GIRS =
-INTROSPECTION_SCANNER_ARGS = --accept-unprefixed
+INTROSPECTION_SCANNER_ARGS = --accept-unprefixed --warn-all
 INTROSPECTION_COMPILER_ARGS =
 
 if HAVE_INTROSPECTION