diff -Naru readline.orig/emacs_keymap.c readline/emacs_keymap.c
--- readline.orig/emacs_keymap.c	2017-11-21 20:44:52.000000000 +0900
+++ readline/emacs_keymap.c	2017-11-21 20:41:35.000000000 +0900
@@ -22,6 +22,7 @@
 #if !defined (BUFSIZ)
 #include <stdio.h>
 #endif /* !BUFSIZ */
+#include <signal.h>
 
 #include "readline.h"
 
@@ -58,7 +59,11 @@
   { ISFUNC, rl_unix_word_rubout },		/* Control-w */
   { ISKMAP, (rl_command_func_t *)emacs_ctlx_keymap },	/* Control-x */
   { ISFUNC, rl_yank },				/* Control-y */
+#ifdef SIGTSTP
+  { ISFUNC, rl_suspend },			/* Control-z */
+#else
   { ISFUNC, (rl_command_func_t *)0x0 },		/* Control-z */
+#endif
   { ISKMAP, (rl_command_func_t *)emacs_meta_keymap }, /* Control-[ */
   { ISFUNC, (rl_command_func_t *)0x0 },		/* Control-\ */
   { ISFUNC, rl_char_search },			/* Control-] */
diff -Naru readline.orig/keymaps.c readline/keymaps.c
--- readline.orig/keymaps.c	2017-11-21 20:44:52.000000000 +0900
+++ readline/keymaps.c	2017-11-21 20:48:55.000000000 +0900
@@ -32,6 +32,7 @@
 #endif /* HAVE_STDLIB_H */
 
 #include <stdio.h>	/* for FILE * definition for readline.h */
+#include <signal.h>
 
 #include "readline.h"
 #include "rlconf.h"
@@ -113,6 +114,9 @@
   newmap[TAB].function = rl_insert;
   newmap[RUBOUT].function = rl_rubout;	/* RUBOUT == 127 */
   newmap[CTRL('H')].function = rl_rubout;
+#ifdef SIGTSTP
+  newmap[CTRL('Z')].function = rl_suspend;
+#endif
 
 #if KEYMAP_SIZE > 128
   /* Printing characters in ISO Latin-1 and some 8-bit character sets. */
diff -Naru readline.orig/misc.c readline/misc.c
--- readline.orig/misc.c	2017-11-21 20:44:52.000000000 +0900
+++ readline/misc.c	2017-11-21 21:31:47.000000000 +0900
@@ -40,6 +40,7 @@
 #endif
 
 #include <stdio.h>
+#include <signal.h>
 
 /* System-specific feature definitions and include files. */
 #include "rldefs.h"
@@ -690,3 +691,14 @@
 
   return 0;
 }
+
+/* Suspend. */
+#ifdef SIGTSTP
+int
+rl_suspend (count, key)
+     int count, key;
+{
+  kill(0, SIGTSTP);
+  return 0;
+}
+#endif
diff -Naru readline.orig/readline.h readline/readline.h
--- readline.orig/readline.h	2017-11-21 20:44:52.000000000 +0900
+++ readline/readline.h	2017-11-21 20:59:40.000000000 +0900
@@ -141,6 +141,9 @@
 /* Bindable commands to change the insert mode (insert or overwrite) */
 extern int rl_overwrite_mode PARAMS((int, int));
 
+/* Bindable commands to suspend. */
+extern int rl_suspend PARAMS((int, int));
+
 /* Bindable commands for managing key bindings. */
 extern int rl_re_read_init_file PARAMS((int, int));
 extern int rl_dump_functions PARAMS((int, int));
diff -Naru readline.orig/rltty.c readline/rltty.c
--- readline.orig/rltty.c	2017-11-21 20:44:52.000000000 +0900
+++ readline/rltty.c	2017-11-21 21:02:49.000000000 +0900
@@ -574,6 +574,10 @@
   tiop->c_cc[VLNEXT] = _POSIX_VDISABLE;
 #endif
 
+#if defined (VSUSP)
+  tiop->c_cc[VSUSP] = _POSIX_VDISABLE;
+#endif
+
 #if defined (VDSUSP)
   tiop->c_cc[VDSUSP] = _POSIX_VDISABLE;
 #endif
diff -Naru readline.orig/stamp-h readline/stamp-h
--- readline.orig/stamp-h	1970-01-01 09:00:00.000000000 +0900
+++ readline/stamp-h	2017-11-21 20:11:13.000000000 +0900
@@ -0,0 +1 @@
+
diff -Naru readline.orig/vi_keymap.c readline/vi_keymap.c
--- readline.orig/vi_keymap.c	2017-11-21 20:44:52.000000000 +0900
+++ readline/vi_keymap.c	2017-11-21 20:42:25.000000000 +0900
@@ -58,7 +58,11 @@
   { ISFUNC, rl_vi_unix_word_rubout },		/* Control-w */
   { ISFUNC, (rl_command_func_t *)0x0 },		/* Control-x */
   { ISFUNC, rl_yank },				/* Control-y */
+#ifndef SIGTSTP
+  { ISFUNC, rl_suspend },			/* Control-z */
+#else
   { ISFUNC, (rl_command_func_t *)0x0 },		/* Control-z */
+#endif
 
   { ISFUNC, (rl_command_func_t *)0x0 },		/* Control-[ */	/* vi_escape_keymap */
   { ISFUNC, (rl_command_func_t *)0x0 },		/* Control-\ */