diff --git a/libc/include/netinet/icmp6.h b/libc/include/netinet/icmp6.h
index e3e6e9a..eca7b45 100644
--- a/libc/include/netinet/icmp6.h
+++ b/libc/include/netinet/icmp6.h
@@ -66,6 +66,7 @@
 #define _NETINET_ICMP6_H_
 
 #include <netinet/in.h> /* android-added: glibc source compatibility. */
+#include <sys/cdefs.h>
 
 #define ICMPV6_PLD_MAXLEN	1232	/* IPV6_MMTU - sizeof(struct ip6_hdr)
 					   - sizeof(struct icmp6_hdr) */