honor CFLAGS

Index: Makefile
--- Makefile.orig
+++ Makefile
@@ -114,7 +114,7 @@ haxelib_unix:
 	cd $(CURDIR)/extra/haxelib_src && \
 	HAXE_STD_PATH=$(CURDIR)/std $(CURDIR)/$(HAXE_OUTPUT) client.hxml && \
 	nekotools boot -c run.n
-	$(CC) $(CURDIR)/extra/haxelib_src/run.c -o $(HAXELIB_OUTPUT) -lneko $(HAXELIB_LFLAGS)
+	$(CC) $(CFLAGS) $(CURDIR)/extra/haxelib_src/run.c -o $(HAXELIB_OUTPUT) -lneko $(HAXELIB_LFLAGS)
 
 # haxelib should depends on haxe, but we don't want to do that...
 ifeq ($(SYSTEM_NAME),Windows)
