Remove old scripts/minicom.sh and cleanup microcom.c a bit more.

Use s# instead of atoi, meantion -s default in help text, use toybuf instead
of stack buf, reuse i instead of declaring a separate ssize_t, FLAG() macro.
diff --git a/scripts/minicom.sh b/scripts/minicom.sh
deleted file mode 100755
index f47d096..0000000
--- a/scripts/minicom.sh
+++ /dev/null
@@ -1,18 +0,0 @@
-#!/bin/bash
-
-# If you want to use toybox netcat to talk to a serial port, use this.
-
-if [ ! -c "$1" ]
-then
-  echo "usage: minicom.sh /dev/ttyS0"
-  exit 1
-fi
-
-SPEED="$2"
-[ -z "$SPEED" ] && SPEED=115200
-
-stty $SPEED -F "$1"
-stty raw -echo -ctlecho -F "$1"
-stty raw -echo  # Need to do it on stdin, too.
-./toybox netcat -f "$1"
-stty cooked echo  # Put stdin back.
diff --git a/toys/net/microcom.c b/toys/net/microcom.c
index 6f88ad4..62b020f 100644
--- a/toys/net/microcom.c
+++ b/toys/net/microcom.c
@@ -2,7 +2,7 @@
  *
  * Copyright 2017 The Android Open Source Project.
 
-USE_MICROCOM(NEWTOY(microcom, "<1>1s:X", TOYFLAG_USR|TOYFLAG_BIN))
+USE_MICROCOM(NEWTOY(microcom, "<1>1s#=115200X", TOYFLAG_USR|TOYFLAG_BIN))
 
 config MICROCOM
   bool "microcom"
@@ -12,7 +12,7 @@
 
     Simple serial console.
 
-    -s	Set baud rate to SPEED
+    -s	Set baud rate to SPEED (default 115200)
     -X	Ignore ^@ (send break) and ^] (exit)
 */
 
@@ -20,7 +20,7 @@
 #include "toys.h"
 
 GLOBALS(
-  char *s;
+  long s;
 
   int fd;
   struct termios original_stdin_state, original_fd_state;
@@ -36,10 +36,7 @@
 void microcom_main(void)
 {
   struct pollfd fds[2];
-  int i, speed;
-
-  if (!TT.s) speed = 115200;
-  else speed = atoi(TT.s);
+  int i;
 
   // Open with O_NDELAY, but switch back to blocking for reads.
   TT.fd = xopen(*toys.optargs, O_RDWR | O_NOCTTY | O_NDELAY);
@@ -47,36 +44,33 @@
     perror_exit_raw(*toys.optargs);
 
   // Set both input and output to raw mode.
-  xset_terminal(TT.fd, 1, speed, &TT.original_fd_state);
+  xset_terminal(TT.fd, 1, TT.s, &TT.original_fd_state);
   set_terminal(0, 1, 0, &TT.original_stdin_state);
   // ...and arrange to restore things, however we may exit.
   sigatexit(restore_states);
 
   fds[0].fd = TT.fd;
-  fds[0].events = POLLIN;
   fds[1].fd = 0;
-  fds[1].events = POLLIN;
+  fds[0].events = fds[1].events = POLLIN;
 
   while (poll(fds, 2, -1) > 0) {
-    char buf[BUFSIZ];
 
     // Read from connection, write to stdout.
     if (fds[0].revents) {
-      ssize_t n = read(TT.fd, buf, sizeof(buf));
-      if (n > 0) xwrite(0, buf, n);
+      if (0 < (i = read(TT.fd, toybuf, sizeof(toybuf)))) xwrite(0, toybuf, i);
       else break;
     }
 
     // Read from stdin, write to connection.
     if (fds[1].revents) {
-      if (read(0, buf, 1) != 1) break;
-      if (!(toys.optflags & FLAG_X)) {
-        if (!*buf) {
+      if (read(0, toybuf, 1) != 1) break;
+      if (!FLAG(X)) {
+        if (!*toybuf) {
           tcsendbreak(TT.fd, 0);
           continue;
-        } else if (*buf == (']'-'@')) break;
+        } else if (*toybuf == (']'-'@')) break;
       }
-      xwrite(TT.fd, buf, 1);
+      xwrite(TT.fd, toybuf, 1);
     }
   }
 }