Revert "Sync readline/ to version 7.0 alpha"

This reverts commit b558ff043d41ba8d17a82f5f9ae5f9dade66160e.
This reverts commit 4a11f2065906976675808364ddbd1c0f77eea41f.

The initial import commit failed to retain local changes made to
readline's configure.in (and the commit message erroneously stated that
there were no local changes that needed to be reapplied).  Also the
import caused a couple of build errors and a scattering of testsuite
regressions throughout many arches.  It's probably better to start over
with this import, hopefully more carefully next time.

readline/examples/excallback.c

@@ -40,14 +40,13 @@ Copyright (C) 1999 Jeff Solomon
 #include <config.h>
 #endif
 
+#include <stdio.h>
 #include <sys/types.h>
 
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>
 #endif
-#include <stdlib.h>
 
-#include <stdio.h>
 #include <termios.h>	/* xxx - should make this more general */
 
 #ifdef READLINE_LIBRARY
@@ -56,10 +55,6 @@ Copyright (C) 1999 Jeff Solomon
 #  include <readline/readline.h>
 #endif
 
-#ifndef STDIN_FILENO
-#  define STDIN_FILENO 0
-#endif
-
 /* This little examples demonstrates the alternate interface to using readline.
  * In the alternate interface, the user maintains control over program flow and
  * only calls readline when STDIN is readable. Using the alternate interface,