diff --git a/programs/Makefile b/programs/Makefile
index 93bbb66..4c05d91 100644
--- a/programs/Makefile
+++ b/programs/Makefile
@@ -3,8 +3,8 @@
 # To compile with PKCS11: add "-lpkcs11-helper" to LDFLAGS
 
 CFLAGS	?= -O2
-WARNING_CFLAGS ?= -Wall -W
-WARNING_CXXFLAGS ?= -Wall -W
+WARNING_CFLAGS ?= -Wall -Wextra
+WARNING_CXXFLAGS ?= -Wall -Wextra
 LDFLAGS ?=
 
 LOCAL_CFLAGS = $(WARNING_CFLAGS) -I../include -D_FILE_OFFSET_BITS=64