Restructures birdc and birdcl to merge duplicated code.

The BIRD client code is restructured that most of the code (including
main function) is shared in client.c, while birdc.c and birdcl.c contain
just I/O-specific callbacks. This removes all duplicated code from
variant-specific files.

client/birdcl.c

@@ -0,0 +1,165 @@
+/*
+ *	BIRD Client - Light variant I/O
+ *
+ *	(c) 1999--2004 Martin Mares <mj@ucw.cz>
+ *      (c) 2013 Tomas Hlavacek <tomas.hlavacek@nic.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <termios.h>
+
+#include <sys/ioctl.h>
+#include <signal.h>
+
+#include "nest/bird.h"
+#include "lib/resource.h"
+#include "lib/string.h"
+#include "client/client.h"
+#include "sysdep/unix/unix.h"
+
+#define INPUT_BUF_LEN 2048
+
+struct termios tty_save;
+
+void
+input_start_list(void)
+{
+  /* Empty in non-ncurses version. */
+}
+
+void
+input_stop_list(void)
+{
+  /* Empty in non-ncurses version. */
+}
+
+void
+input_notify(int prompt)
+{
+  /* No ncurses -> no status to reveal/hide, print prompt manually. */
+  if (!prompt)
+    return;
+
+  printf("bird> ");
+  fflush(stdout);
+}
+
+
+static int
+lastnb(char *str, int i)
+{
+  while (i--)
+    if ((str[i] != ' ') && (str[i] != '\t'))
+      return str[i];
+
+  return 0;
+}
+
+void
+input_read(void)
+{
+  char buf[INPUT_BUF_LEN];
+
+  if ((fgets(buf, INPUT_BUF_LEN, stdin) == NULL) || (buf[0] == 0))
+  {
+    putchar('\n');
+    cleanup();
+    exit(0);
+  }
+
+  int l = strlen(buf);
+  if ((l+1) == INPUT_BUF_LEN)
+    {
+      printf("Input too long.\n");
+      return;
+    }
+
+  if (buf[l-1] == '\n')
+    buf[--l] = '\0';
+
+  if (!interactive)
+    printf("%s\n", buf);
+
+  if (l == 0)
+    return;
+
+  if (lastnb(buf, l) == '?')
+    {
+      cmd_help(buf, strlen(buf));
+      return;
+    }
+
+  submit_command(buf);
+}
+
+static struct termios stored_tty;
+static int more_active = 0;
+
+void
+more_begin(void)
+{
+  static struct termios tty;
+
+  tty = stored_tty;
+  tty.c_lflag &= (~ECHO);
+  tty.c_lflag &= (~ICANON);
+
+  if (tcsetattr (0, TCSANOW, &tty) < 0)
+    die("tcsetattr: %m");
+
+  more_active = 1;
+}
+
+void
+more_end(void)
+{
+  more_active = 0;
+
+  if (tcsetattr (0, TCSANOW, &stored_tty) < 0)
+    die("tcsetattr: %m");
+}
+
+static void
+sig_handler(int signal)
+{
+  cleanup();
+  exit(0);
+}
+
+void
+input_init(void)
+{
+  if (!interactive)
+    return;
+
+  if (tcgetattr(0, &stored_tty) < 0)
+    die("tcgetattr: %m");
+
+  if (signal(SIGINT, sig_handler) == SIG_IGN)
+    signal(SIGINT, SIG_IGN);
+  if (signal(SIGTERM, sig_handler) == SIG_IGN)
+    signal(SIGTERM, SIG_IGN);
+
+  struct winsize tws;
+  if (ioctl(0, TIOCGWINSZ, &tws) == 0)
+    {
+      term_lns = tws.ws_row;
+      term_cls = tws.ws_col;
+    }
+  else
+    {
+       term_lns = 25;
+       term_cls = 80;
+    }
+}
+
+void
+cleanup(void)
+{
+  if (more_active)
+    more_end();
+}