Update code

src/Makefile

@@ -2,7 +2,7 @@
 BIN=smartdns 
 OBJS_LIB=lib/rbtree.o lib/art.o lib/bitops.o
 OBJS=smartdns.o fast_ping.o dns_client.o dns_server.o dns.o util.o tlog.o conf.o dns_cache.o $(OBJS_LIB)
-CFLAGS=-O2 -Wall -Wstrict-prototypes -fno-omit-frame-pointer -Wstrict-aliasing 
+CFLAGS +=-O2 -Wall -Wstrict-prototypes -fno-omit-frame-pointer -Wstrict-aliasing 
 CFLAGS +=-Iinclude
 CFLAGS += -DBASE_FILE_NAME=\"$(notdir $<)\"
 CXXFLAGS=-O2 -Wall -std=c++11