Patch from Hideki IWAMOTO, output debugging messages to stderr
diff --git a/networking/tftp.c b/networking/tftp.c
index 0bc562d..f00b64b 100644
--- a/networking/tftp.c
+++ b/networking/tftp.c
@@ -292,10 +292,10 @@
 			len = cp - buf;
 
 #ifdef CONFIG_FEATURE_TFTP_DEBUG
-			printf("sending %u bytes\n", len);
+			fprintf(stderr, "sending %u bytes\n", len);
 			for (cp = buf; cp < &buf[len]; cp++)
-				printf("%02x ", *cp);
-			printf("\n");
+				fprintf(stderr, "%02x ", *cp);
+			fprintf(stderr, "\n");
 #endif
 			if (sendto(socketfd, buf, len, 0,
 					(struct sockaddr *) &sa, sizeof(sa)) < 0) {
@@ -371,7 +371,7 @@
 		tmp = ntohs(*((unsigned short *) &buf[2]));
 
 #ifdef CONFIG_FEATURE_TFTP_DEBUG
-		printf("received %d bytes: %04x %04x\n", len, opcode, tmp);
+		fprintf(stderr, "received %d bytes: %04x %04x\n", len, opcode, tmp);
 #endif
 
 		if (opcode == TFTP_ERROR) {
@@ -420,7 +420,7 @@
 				                         opcode = TFTP_ACK;
 						 }
 #ifdef CONFIG_FEATURE_TFTP_DEBUG
-						 printf("using blksize %u\n", blksize);
+						 fprintf(stderr, "using blksize %u\n", blksize);
 #endif
 					         tftp_bufsize = blksize + 4;
 						 block_nr = 0;
@@ -567,7 +567,7 @@
 	port = bb_lookup_port(argv[optind + 1], "udp", 69);
 
 #ifdef CONFIG_FEATURE_TFTP_DEBUG
-	printf("using server \"%s\", remotefile \"%s\", "
+	fprintf(stderr, "using server \"%s\", remotefile \"%s\", "
 		"localfile \"%s\".\n",
 		inet_ntoa(*((struct in_addr *) host->h_addr)),
 		remotefile, localfile);