The <arpa/tftp.h> header is needed by inetutils.

diff -N -a -u -r /home/fornwall/lib/android-ndk/platforms/android-21/arch-arm/usr/include/arpa/tftp.h ./usr/include/arpa/tftp.h
--- /home/fornwall/lib/android-ndk/platforms/android-21/arch-arm/usr/include/arpa/tftp.h	1969-12-31 19:00:00.000000000 -0500
+++ ./usr/include/arpa/tftp.h	2015-05-12 15:40:31.648145474 -0400
@@ -0,0 +1,82 @@
+/*
+ * Copyright (c) 1983, 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.
+ * 4. 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.
+ *
+ *	@(#)tftp.h	8.1 (Berkeley) 6/2/93
+ */
+
+#ifndef _ARPA_TFTP_H
+#define	_ARPA_TFTP_H 1
+
+/*
+ * Trivial File Transfer Protocol (IEN-133)
+ */
+#define	SEGSIZE		512		/* data segment size */
+
+/*
+ * Packet types.
+ */
+#define	RRQ	01				/* read request */
+#define	WRQ	02				/* write request */
+#define	DATA	03				/* data packet */
+#define	ACK	04				/* acknowledgement */
+#define	ERROR	05				/* error code */
+
+struct	tftphdr {
+	short	th_opcode;			/* packet type */
+	union {
+		char	tu_padding[3];		/* sizeof() compat */
+		struct {
+			union {
+				unsigned short	tu_block;	/* block # */
+				short	tu_code;		/* error code */
+			} __attribute__ ((__packed__)) th_u3;
+			char tu_data[0];	/* data or error string */
+		} __attribute__ ((__packed__)) th_u2;
+		char	tu_stuff[0];		/* request packet stuff */
+	} __attribute__ ((__packed__)) th_u1;
+} __attribute__ ((__packed__));
+
+#define	th_block	th_u1.th_u2.th_u3.tu_block
+#define	th_code		th_u1.th_u2.th_u3.tu_code
+#define	th_stuff	th_u1.tu_stuff
+#define	th_data		th_u1.th_u2.tu_data
+#define	th_msg		th_u1.th_u2.tu_data
+
+/*
+ * Error codes.
+ */
+#define	EUNDEF		0		/* not defined */
+#define	ENOTFOUND	1		/* file not found */
+#define	EACCESS		2		/* access violation */
+#define	ENOSPACE	3		/* disk full or allocation exceeded */
+#define	EBADOP		4		/* illegal TFTP operation */
+#define	EBADID		5		/* unknown transfer ID */
+#define	EEXISTS		6		/* file already exists */
+#define	ENOUSER		7		/* no such user */
+
+#endif /* arpa/tftp.h */