Add TFTP upload spinner

tftp.c

@@ -305,6 +305,8 @@ inline bool tftp_is_valid_filename(const char *filename)
 	return strlen(filename) <= 255 && is_netascii(filename);
 }
 
+static const char *spinner = "\\|/-";
+
 int tftp_put(struct nmrpd_args *args)
 {
 	struct sockaddr_in addr;
@@ -416,6 +418,10 @@ int tftp_put(struct nmrpd_args *args)
 					}
 				}
 
+				printf("%c ", spinner[block & 3]);
+				fflush(stdout);
+				printf("\b\b");
+
 				pkt_mknum(tx, DATA);
 				pkt_mknum(tx + 2, block);
 				len = read(fd, tx + 4, blksize);