--- ../busybox-1.26.2.orig/networking/ifconfig.c	2016-12-10 20:46:36.000000000 +0300
+++ ./networking/ifconfig.c	2017-01-18 11:09:10.064194554 +0300
@@ -130,11 +130,13 @@
 #endif
 
 #if ENABLE_FEATURE_IPV6
+# if !defined(__ANDROID__) || (defined(__ANDROID__) && __ANDROID_API__ < 21)
 struct in6_ifreq {
 	struct in6_addr ifr6_addr;
 	uint32_t ifr6_prefixlen;
 	int ifr6_ifindex;
 };
+# endif
 #endif
 
 /*
--- ../busybox-1.26.2.orig/networking/interface.c	2016-12-10 20:46:36.000000000 +0300
+++ ./networking/interface.c	2017-01-18 11:08:06.780193597 +0300
@@ -59,11 +59,13 @@
 /*
  * This is from linux/include/net/ipv6.h
  */
+#  if !defined(__ANDROID__) || (defined(__ANDROID__) && __ANDROID_API__ < 21)
 struct in6_ifreq {
 	struct in6_addr ifr6_addr;
 	uint32_t ifr6_prefixlen;
 	unsigned int ifr6_ifindex;
 };
+#  endif
 # endif
 #endif /* HAVE_AFINET6 */