diff --git a/test/zdtm/lib/Makefile b/test/zdtm/lib/Makefile
index 2be301113..0162e8c6e 100644
--- a/test/zdtm/lib/Makefile
+++ b/test/zdtm/lib/Makefile
@@ -1,4 +1,4 @@
-CFLAGS	= -g -O2 -Wall -Werror -Wno-unused-result
+CFLAGS	= -g -O2 -Wall -Werror -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=0
 
 LIB	= libzdtmtst.a
 
diff --git a/test/zdtm/live/static/Makefile b/test/zdtm/live/static/Makefile
index f6af812d8..00f9943d2 100644
--- a/test/zdtm/live/static/Makefile
+++ b/test/zdtm/live/static/Makefile
@@ -1,7 +1,7 @@
 LIBDIR	= ../../lib
 LIB	= $(LIBDIR)/libzdtmtst.a
 override CPPFLAGS += -I$(LIBDIR)
-CFLAGS	= -g -O2 -Wall -Werror -Wno-unused-result
+CFLAGS	= -g -O2 -Wall -Werror -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=0
 
 TST_NOFILE	=				\
 		busyloop00			\