diff -Naur a/src/tingle/makefile b/src/tingle/makefile
--- a/src/tingle/makefile	2019-06-09 21:09:50.677101222 +0300
+++ b/src/tingle/makefile	2019-06-19 05:57:15.196603384 +0300
@@ -1,7 +1,7 @@
 PROGRAM=tingle
 SOURCES=tingle.c
-CFLAGS=-O2 -Wall -pedantic -std=c99 -lpthread
-LDFLAGS=-lm -pthread
+CFLAGS+=-Wall -pedantic -std=c99 -lpthread
+LDFLAGS+=-lm -pthread
 HAVE_ALSA := 0
 
 ALSA_TEST := $(shell pkg-config --exists alsa 1>&2 2>/dev/null; echo $$?)
