--- a/ntp_io_linux.c
+++ b/ntp_io_linux.c
@@ -49,6 +49,14 @@
 #include "sys_linux.h"
 #include "util.h"
 
+// missing in NDK linux/ethtool.h
+#if defined(__ANDROID__)
+static inline __u32 ethtool_cmd_speed(const struct ethtool_cmd *ep)
+{
+	return (ep->speed_hi << 16) | ep->speed;
+}
+#endif
+
 struct Interface {
   char name[IF_NAMESIZE];
   int if_index;