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.

Change-Id: I111f9887f3812469b411b9cf5124d9dd624f19f7
diff --git a/libc/include/net/if_dl.h b/libc/include/net/if_dl.h
deleted file mode 100644
index 1f0c080..0000000
--- a/libc/include/net/if_dl.h
+++ /dev/null
@@ -1,87 +0,0 @@
-/*	$NetBSD: if_dl.h,v 1.18 2005/12/11 23:05:24 thorpej Exp $	*/
-
-/*
- * Copyright (c) 1990, 1993
- *	The Regents of the University of California.  All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- * 3. Neither the name of the University nor the names of its contributors
- *    may be used to endorse or promote products derived from this software
- *    without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- *	@(#)if_dl.h	8.1 (Berkeley) 6/10/93
- */
-
-/*
- * A Link-Level Sockaddr may specify the interface in one of two
- * ways: either by means of a system-provided index number (computed
- * anew and possibly differently on every reboot), or by a human-readable
- * string such as "il0" (for managerial convenience).
- *
- * Census taking actions, such as something akin to SIOCGCONF would return
- * both the index and the human name.
- *
- * High volume transactions (such as giving a link-level ``from'' address
- * in a recvfrom or recvmsg call) may be likely only to provide the indexed
- * form, (which requires fewer copy operations and less space).
- *
- * The form and interpretation  of the link-level address is purely a matter
- * of convention between the device driver and its consumers; however, it is
- * expected that all drivers for an interface of a given if_type will agree.
- */
-
-#ifndef _NET_IF_DL_H_
-#define _NET_IF_DL_H_
-
-#include <sys/socket.h>
-
-/*
- * Structure of a Link-Level sockaddr:
- */
-struct sockaddr_dl {
-	u_char	    sdl_len;	/* Total length of sockaddr */
-	sa_family_t sdl_family;	/* AF_LINK */
-	u_int16_t   sdl_index;	/* if != 0, system given index for interface */
-	u_char	    sdl_type;	/* interface type */
-	u_char	    sdl_nlen;	/* interface name length, no trailing 0 reqd. */
-	u_char	    sdl_alen;	/* link level address length */
-	u_char	    sdl_slen;	/* link layer selector length */
-	char	    sdl_data[12]; /* minimum work area, can be larger;
-				     contains both if name and ll address */
-};
-
-/* We do arithmetic directly with these, so keep them char instead of void */
-#define LLADDR(s) ((char *)((s)->sdl_data + (s)->sdl_nlen))
-#define CLLADDR(s) ((const char *)((s)->sdl_data + (s)->sdl_nlen))
-
-#ifndef _KERNEL
-
-#include <sys/cdefs.h>
-
-__BEGIN_DECLS
-void	link_addr(const char *, struct sockaddr_dl *);
-char	*link_ntoa(const struct sockaddr_dl *);
-__END_DECLS
-
-#endif /* !_KERNEL */
-
-#endif /* !_NET_IF_DL_H_ */
diff --git a/libc/netbsd/net/getnameinfo.c b/libc/netbsd/net/getnameinfo.c
index 8a1e95e..d8ac037 100644
--- a/libc/netbsd/net/getnameinfo.c
+++ b/libc/netbsd/net/getnameinfo.c
@@ -53,7 +53,9 @@
 #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_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));
 
 // This should be synchronized to ResponseCode.h
@@ -123,7 +127,7 @@
 	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);
@@ -408,7 +412,7 @@
 #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
@@ -546,6 +550,7 @@
 #endif /* INET6 */
 
 
+#if defined(ANDROID_CHANGES) && defined(AF_LINK)
 /*
  * getnameinfo_link():
  * Format a link-layer address into a printable format, paying attention to
@@ -623,6 +628,7 @@
 		    (size_t)sdl->sdl_alen, host, hostlen);
 	}
 }
+#endif
 
 static int
 hexname(cp, len, host, hostlen)