Only bring in linux/ipv6.h if linux AND glibc.
#include <sys/utsname.h>
#include <netinet/in.h>
-#ifdef __linux__
-# define _LINUX_IN6_H
-# include <linux/ipv6.h>
-#endif
#include <ctype.h>
#include <errno.h>
#include <netinet/in.h>
-#ifdef __linux__
+#if defined(__linux__) && defined(__GLIBC__)
# define _LINUX_IN6_H
# include <linux/ipv6.h>
#endif
#include <netinet/ip6.h>
#include <netinet/icmp6.h>
-#ifdef __linux__
-# define _LINUX_IN6_H
-# include <linux/ipv6.h>
-#endif
-
#include <errno.h>
#include <fcntl.h>
#include <stddef.h>