--- a/debian/rules	2019-09-25 08:13:52.161228904 +0100
--- b/debian/rules	2019-09-25 08:16:29.205784247 +0100
@@ -5,7 +5,7 @@
 export DEB_TARGET_MULTIARCH ?= $(shell dpkg-architecture -qDEB_TARGET_MULTIARCH)
 
 CC=gcc
-CFLAGS=-std=gnu99 -g -O2 -Wall -D TB_NO_THREADS -D TB_NO_HW_POP_COUNT -I.. $(CPPFLAGS)
+CFLAGS=-std=gnu99 $(shell dpkg-buildflags --get CFLAGS) -Wall -D TB_NO_THREADS -D TB_NO_HW_POP_COUNT -I.. $(CPPFLAGS)
 
 %:
 	dh $@