added -Wformat-security flag, as recommended by @pixelb

programs/Makefile

@@ -30,7 +30,7 @@ CPPFLAGS+= -I$(ZSTDDIR) -I$(ZSTDDIR)/common -I$(ZSTDDIR)/compress \
 CFLAGS  ?= -O3
 DEBUGFLAGS = -g -Wall -Wextra -Wcast-qual -Wcast-align -Wshadow \
           -Wstrict-aliasing=1 -Wswitch-enum -Wdeclaration-after-statement \
-          -Wstrict-prototypes -Wundef -Wpointer-arith
+          -Wstrict-prototypes -Wundef -Wpointer-arith -Wformat-security
 CFLAGS  += $(DEBUGFLAGS) $(MOREFLAGS)
 FLAGS    = $(CPPFLAGS) $(CFLAGS) $(LDFLAGS)