Do not override MacPorts optimization flags.
--- Makefile.orig	2018-11-16 08:40:02.000000000 -0600
+++ Makefile	2023-09-30 01:53:36.000000000 -0500
@@ -3,7 +3,7 @@
 MANDIR?=	$(PREFIX)/share/man/man8
 
 CC?=		cc
-CFLAGS+=	-Wall -O2 -g -std=c99
+CFLAGS+=	-Wall -g -std=c99
 
 all: vmtouch vmtouch.8