-CFLAGS := -g -O2 -fPIE -fstack-protector-strong -Wall -Wextra -Wconversion
-CPPFLAGS := -D_FORTIFY_SOURCE=2
-LDFLAGS := -fPIE -pie -Wl,-z,relro -Wl,-z,now
+CFLAGS := -g -O2 -fPIE -fstack-protector-strong -Wall -Wextra -Wconversion $(CFLAGS)
+CPPFLAGS := -D_FORTIFY_SOURCE=2 $(CPPFLAGS)
+LDFLAGS := -fPIE -pie -Wl,-z,relro -Wl,-z,now $(LDFLAGS)
ptyas: ptyas.c