--- a/Makefile
+++ b/Makefile
@@ -2,11 +2,11 @@ prefix ?= /usr/local
 libdir ?= $(prefix)/lib
 includedir ?= $(prefix)/include
 
-CFLAGS:=-Wall -g -Wextra $(shell pkg-config glib-2.0 --cflags) -Wswitch-enum -std=gnu11 -O2 -fPIC
+CFLAGS+=-Wall -g -Wextra $(shell pkg-config glib-2.0 --cflags) -Wswitch-enum -std=gnu11 -fPIC
 SO_VERSION = 0
 VERSION = 0
 INSTALL = install
-LDLIBS:=$(shell pkg-config glib-2.0 --libs) -lz
+LDLIBS+=$(shell pkg-config glib-2.0 --libs) -lz
 
 BOTLIBS := -Wl,-rpath,.
 
