diff --git a/cddl/lib/libavl/Makefile b/cddl/lib/libavl/Makefile
index f4db92f01291..856d12c22082 100644
--- a/cddl/lib/libavl/Makefile
+++ b/cddl/lib/libavl/Makefile
@@ -4,7 +4,7 @@
 
 LIB=	avl
 SRCS=	avl.c
-WARNS?=	0
+WARNS?=	3
 CFLAGS+= -I${.CURDIR}/../../../sys/cddl/compat/opensolaris
 CFLAGS+= -I${.CURDIR}/../../../sys/cddl/contrib/opensolaris/uts/common
 
diff --git a/cddl/lib/libctf/Makefile b/cddl/lib/libctf/Makefile
index a79aef5ac6ce..e41ad3701941 100644
--- a/cddl/lib/libctf/Makefile
+++ b/cddl/lib/libctf/Makefile
@@ -18,7 +18,7 @@ SRCS=		ctf_create.c \
 		ctf_util.c
 MAN=		ctf.5
 
-WARNS?=		0
+WARNS?=		2
 CFLAGS+=	-DCTF_OLD_VERSIONS
 
 CFLAGS+=	-I${.CURDIR}/../../../sys/cddl/compat/opensolaris \
diff --git a/cddl/lib/libnvpair/Makefile b/cddl/lib/libnvpair/Makefile
index 98bdb47a94c1..aef3f0b392d5 100644
--- a/cddl/lib/libnvpair/Makefile
+++ b/cddl/lib/libnvpair/Makefile
@@ -12,7 +12,7 @@ SRCS=	libnvpair.c \
 	opensolaris_nvpair.c \
 	opensolaris_nvpair_alloc_fixed.c
 
-WARNS?=	0
+WARNS?=	1
 CFLAGS+= -I${.CURDIR}/../../../cddl/compat/opensolaris/include
 CFLAGS+= -I${.CURDIR}/../../../cddl/contrib/opensolaris/lib/libzpool/common
 CFLAGS+= -I${.CURDIR}/../../../sys/cddl/compat/opensolaris
diff --git a/cddl/lib/libumem/Makefile b/cddl/lib/libumem/Makefile
index 0ce73f8e5f21..56005aa04bd8 100644
--- a/cddl/lib/libumem/Makefile
+++ b/cddl/lib/libumem/Makefile
@@ -4,7 +4,7 @@
 
 LIB=	umem
 SRCS=	umem.c
-WARNS?=	0
+WARNS?=	3
 CFLAGS+= -I${.CURDIR}/../../../cddl/compat/opensolaris/lib/libumem
 
 .include <bsd.lib.mk>
diff --git a/cddl/lib/libuutil/Makefile b/cddl/lib/libuutil/Makefile
index 7521747a4c04..72a7a30f06b9 100644
--- a/cddl/lib/libuutil/Makefile
+++ b/cddl/lib/libuutil/Makefile
@@ -15,7 +15,7 @@ SRCS=	avl.c \
 	uu_pname.c \
 	uu_strtoint.c
 
-WARNS?=	0
+WARNS?=	1
 CFLAGS+= -DNATIVE_BUILD
 CFLAGS+= -I${.CURDIR}/../../../cddl/contrib/opensolaris/lib/libuutil/common
 CFLAGS+= -I${.CURDIR}/../../../sys/cddl/compat/opensolaris