remove an unnecessary m4 script

m4/ax_lib_readline.m4

-# ===========================================================================
-#      http://www.gnu.org/software/autoconf-archive/ax_lib_readline.html
-# ===========================================================================
-#
-# SYNOPSIS
-#
-#   AX_LIB_READLINE
-#
-# DESCRIPTION
-#
-#   Searches for a readline compatible library. If found, defines
-#   `HAVE_LIBREADLINE'. If the found library has the `add_history' function,
-#   sets also `HAVE_READLINE_HISTORY'. Also checks for the locations of the
-#   necessary include files and sets `HAVE_READLINE_H' or
-#   `HAVE_READLINE_READLINE_H' and `HAVE_READLINE_HISTORY_H' or
-#   'HAVE_HISTORY_H' if the corresponding include files exists.
-#
-#   The libraries that may be readline compatible are `libedit',
-#   `libeditline' and `libreadline'. Sometimes we need to link a termcap
-#   library for readline to work, this macro tests these cases too by trying
-#   to link with `libtermcap', `libcurses' or `libncurses' before giving up.
-#
-#   Here is an example of how to use the information provided by this macro
-#   to perform the necessary includes or declarations in a C file:
-#
-#     #ifdef HAVE_LIBREADLINE
-#     #  if defined(HAVE_READLINE_READLINE_H)
-#     #    include <readline/readline.h>
-#     #  elif defined(HAVE_READLINE_H)
-#     #    include <readline.h>
-#     #  else /* !defined(HAVE_READLINE_H) */
-#     extern char *readline ();
-#     #  endif /* !defined(HAVE_READLINE_H) */
-#     char *cmdline = NULL;
-#     #else /* !defined(HAVE_READLINE_READLINE_H) */
-#       /* no readline */
-#     #endif /* HAVE_LIBREADLINE */
-#
-#     #ifdef HAVE_READLINE_HISTORY
-#     #  if defined(HAVE_READLINE_HISTORY_H)
-#     #    include <readline/history.h>
-#     #  elif defined(HAVE_HISTORY_H)
-#     #    include <history.h>
-#     #  else /* !defined(HAVE_HISTORY_H) */
-#     extern void add_history ();
-#     extern int write_history ();
-#     extern int read_history ();
-#     #  endif /* defined(HAVE_READLINE_HISTORY_H) */
-#       /* no history */
-#     #endif /* HAVE_READLINE_HISTORY */
-#
-# LICENSE
-#
-#   Copyright (c) 2008 Ville Laurikari <vl@iki.fi>
-#
-#   Copying and distribution of this file, with or without modification, are
-#   permitted in any medium without royalty provided the copyright notice
-#   and this notice are preserved. This file is offered as-is, without any
-#   warranty.
-
-#serial 6
-
-AU_ALIAS([VL_LIB_READLINE], [AX_LIB_READLINE])
-AC_DEFUN([AX_LIB_READLINE], [
-  AC_CACHE_CHECK([for a readline compatible library],
-                 ax_cv_lib_readline, [
-    ORIG_LIBS="$LIBS"
-    for readline_lib in readline edit editline; do
-      for termcap_lib in "" termcap curses ncurses; do
-        if test -z "$termcap_lib"; then
-          TRY_LIB="-l$readline_lib"
-        else
-          TRY_LIB="-l$readline_lib -l$termcap_lib"
-        fi
-        LIBS="$ORIG_LIBS $TRY_LIB"
-        AC_TRY_LINK_FUNC(readline, ax_cv_lib_readline="$TRY_LIB")
-        if test -n "$ax_cv_lib_readline"; then
-          break
-        fi
-      done
-      if test -n "$ax_cv_lib_readline"; then
-        break
-      fi
-    done
-    if test -z "$ax_cv_lib_readline"; then
-      ax_cv_lib_readline="no"
-    fi
-    LIBS="$ORIG_LIBS"
-  ])
-
-  if test "$ax_cv_lib_readline" != "no"; then
-    LIBS="$LIBS $ax_cv_lib_readline"
-    AC_DEFINE(HAVE_LIBREADLINE, 1,
-              [Define if you have a readline compatible library])
-    AC_CHECK_HEADERS(readline.h readline/readline.h)
-    AC_CACHE_CHECK([whether readline supports history],
-                   ax_cv_lib_readline_history, [
-      ax_cv_lib_readline_history="no"
-      AC_TRY_LINK_FUNC(add_history, ax_cv_lib_readline_history="yes")
-    ])
-    if test "$ax_cv_lib_readline_history" = "yes"; then
-      AC_DEFINE(HAVE_READLINE_HISTORY, 1,
-                [Define if your readline library has \`add_history'])
-      AC_CHECK_HEADERS(history.h readline/history.h)
-    fi
-  fi
-])dnl