diff --git a/lib/libpam/Makefile.inc b/lib/libpam/Makefile.inc
index 2558a61faa10..1787c3448f7e 100644
--- a/lib/libpam/Makefile.inc
+++ b/lib/libpam/Makefile.inc
@@ -26,3 +26,5 @@
 
 SHLIB_MAJOR=	1
 SHLIB_MINOR=	0
+
+WARNS?=		4