Remove the meaningless on Linux if_dl.h header.

This was misleading 'configure' into thinking we actually support AF_LINK,
but we're Linux, so we don't, and we never implemented the functions we
declared here either.

Reported to AOSP by Jun-ya Kato.

(cherry-pick of 5056f1f.)

Change-Id: Ic67f674d2221497c8166994812bb5fc7f0831066

libc/netbsd/net/getnameinfo.c

@@ -53,7 +53,9 @@ __RCSID("$NetBSD: getnameinfo.c,v 1.43 2006/02/17 15:58:26 ginsbach Exp $");
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <net/if.h>
+#if defined(ANDROID_CHANGES) && defined(AF_LINK)
 #include <net/if_dl.h>
+#endif
 #include <net/if_ieee1394.h>
 #include <net/if_types.h>
 #include <netinet/in.h>
@@ -104,8 +106,10 @@ static int ip6_parsenumeric __P((const struct sockaddr *, const char *, char *,
 static int ip6_sa2str __P((const struct sockaddr_in6 *, char *, size_t,
 				 int));
 #endif
+#if defined(ANDROID_CHANGES) && defined(AF_LINK)
 static int getnameinfo_link __P((const struct sockaddr *, socklen_t, char *,
     socklen_t, char *, socklen_t, int));
+#endif
 static int hexname __P((const u_int8_t *, size_t, char *, socklen_t));
 
 /*
@@ -119,7 +123,7 @@ int getnameinfo(const struct sockaddr* sa, socklen_t salen, char* host, size_t h
 	case AF_INET6:
 		return getnameinfo_inet(sa, salen, host, hostlen,
 		    serv, servlen, flags);
-#if 0
+#if defined(ANDROID_CHANGES) && defined(AF_LINK)
 	case AF_LINK:
 		return getnameinfo_link(sa, salen, host, hostlen,
 		    serv, servlen, flags);
@@ -393,7 +397,7 @@ getnameinfo_inet(sa, salen, host, hostlen, serv, servlen, flags)
 #endif
 
 		if (hp) {
-#if 0
+#if defined(ANDROID_CHANGES) && defined(AF_LINK)
 			/*
 			 * commented out, since "for local host" is not
 			 * implemented here - see RFC2553 p30
@@ -531,6 +535,7 @@ ip6_sa2str(sa6, buf, bufsiz, flags)
 #endif /* INET6 */
 
 
+#if defined(ANDROID_CHANGES) && defined(AF_LINK)
 /*
  * getnameinfo_link():
  * Format a link-layer address into a printable format, paying attention to
@@ -608,6 +613,7 @@ getnameinfo_link(const struct sockaddr *sa, socklen_t salen,
 		    (size_t)sdl->sdl_alen, host, hostlen);
 	}
 }
+#endif
 
 static int
 hexname(cp, len, host, hostlen)