diff --git a/Makefile b/Makefile
index 904720c..766ecf2 100644
--- a/Makefile
+++ b/Makefile
@@ -6,8 +6,8 @@ all: bin2png png2bin
 clean:
 	@rm -rf *.o bin2png png2bin
 
-CFLAGS = -D_XOPEN_SOURCE=600 -std=c99 -Wall -Wextra
-LDFLAGS = -lpng
+CFLAGS += -D_XOPEN_SOURCE=600 -std=c99 -Wall -Wextra
+LDFLAGS += -lpng
 
 ifeq ($(PLATFORM_OS), Linux)
 	LDFLAGS += -lm # required for sqrt()