diff -urN a/src/makefile b/src/makefile
--- a/src/makefile	2023-11-04 19:35:24.000000000 -0400
+++ b/src/makefile	2023-11-04 20:11:21.000000000 -0400
@@ -107,11 +107,11 @@
 
 endif
 
-CFLAGS=$(GCCFLAGS) \
+CFLAGS+=$(GCCFLAGS) \
 	-D_REGEX_LARGE_OFFSETS -D_GNU_SOURCE -DSTDC_HEADERS -DHAVE_SNPRINTF \
 	$(if $(NE_NOWCHAR), -DNOWCHAR,) \
 	$(if $(NE_TEST),    -DNE_TEST -coverage,) \
-	$(if $(NE_DEBUG),   -g -O -fsanitize=address -fsanitize=undefined,-O3 -DNDEBUG) \
+	$(if $(NE_DEBUG),   -g -O -fsanitize=address -fsanitize=undefined, -DNDEBUG) \
 	$(if $(NE_TERMCAP), -DNE_TERMCAP,) \
 	$(if $(NE_ANSI),    -DNE_TERMCAP -DNE_ANSI,) \
 	$(OPTS)