diff --git a/Android.mk b/Android.mk
index 4ae22f6..2a41dd5 100644
--- a/Android.mk
+++ b/Android.mk
@@ -47,6 +47,8 @@
 # Always support IPv4.
 LOCAL_CFLAGS += -DINET
 
+LOCAL_CFLAGS += -D_BSD_SOURCE
+
 ifeq ($(DHCPCD_USE_IPV6), yes)
 LOCAL_SRC_FILES += ipv6.c ipv6nd.c dhcp6.c
 LOCAL_SRC_FILES += crypt/sha256.c