--- a/makefile	2018-12-09 14:56:14.827262650 +0200
+++ b/makefile	2018-12-09 14:57:18.787297831 +0200
@@ -32,10 +32,12 @@
 CC = gcc -O4 -Wall -pedantic -fno-strict-aliasing
 
 YACC = bison -d -y
-YACC = yacc -d -S
+YACC = yacc -d
 #YFLAGS = -d -S
 		# -S uses sprintf in yacc parser instead of sprint
 
+LDFLAGS = -Wl,-z,relro,-z,now
+
 OFILES = b.o main.o parse.o proctab.o tran.o lib.o run.o lex.o
 
 SOURCE = awk.h ytab.c ytab.h proto.h awkgram.y lex.c b.c main.c \
@@ -48,7 +50,7 @@
 	 awk.1
 
 a.out:	ytab.o $(OFILES)
-	$(CC) ytab.o $(OFILES) $(ALLOC)  -lm
+	$(CC) $(LDFLAGS) ytab.o $(OFILES) $(ALLOC)  -lm
 
 $(OFILES):	awk.h ytab.h proto.h