dnl need: prefix exec_prefix libdir includedir CC TERMCAP_LIB
dnl require:
dnl	AC_PROG_CC
dnl	BASH_CHECK_LIB_TERMCAP

AC_DEFUN([RL_LIB_READLINE_VERSION],
[
AC_REQUIRE([BASH_CHECK_LIB_TERMCAP])

AC_MSG_CHECKING([version of installed readline library])

# What a pain in the ass this is.

# save cpp and ld options
_save_CFLAGS="$CFLAGS"
_save_LDFLAGS="$LDFLAGS"
_save_LIBS="$LIBS"

# Don't set ac_cv_rl_prefix if the caller has already assigned a value.  This
# allows the caller to do something like $_rl_prefix=$withval if the user
# specifies --with-installed-readline=PREFIX as an argument to configure

if test -z "$ac_cv_rl_prefix"; then
test "x$prefix" = xNONE && ac_cv_rl_prefix=$ac_default_prefix || ac_cv_rl_prefix=${prefix}
fi

eval ac_cv_rl_includedir=${ac_cv_rl_prefix}/include
eval ac_cv_rl_libdir=${ac_cv_rl_prefix}/lib

LIBS="$LIBS -lreadline ${TERMCAP_LIB}"
CFLAGS="$CFLAGS -I${ac_cv_rl_includedir}"
LDFLAGS="$LDFLAGS -L${ac_cv_rl_libdir}"

AC_CACHE_VAL(ac_cv_rl_version,
[AC_TRY_RUN([
#include <stdio.h>
#include <readline/readline.h>

extern int rl_gnu_readline_p;

main()
{
	FILE *fp;
	fp = fopen("conftest.rlv", "w");
	if (fp == 0)
		exit(1);
	if (rl_gnu_readline_p != 1)
		fprintf(fp, "0.0\n");
	else
		fprintf(fp, "%s\n", rl_library_version ? rl_library_version : "0.0");
	fclose(fp);
	exit(0);
}
],
ac_cv_rl_version=`cat conftest.rlv`,
ac_cv_rl_version='0.0',
ac_cv_rl_version='4.2')])

CFLAGS="$_save_CFLAGS"
LDFLAGS="$_save_LDFLAGS"
LIBS="$_save_LIBS"

RL_MAJOR=0
RL_MINOR=0

# (
case "$ac_cv_rl_version" in
2*|3*|4*|5*|6*|7*|8*|9*)
	RL_MAJOR=`echo $ac_cv_rl_version | sed 's:\..*$::'`
	RL_MINOR=`echo $ac_cv_rl_version | sed -e 's:^.*\.::' -e 's:[[a-zA-Z]]*$::'`
	;;
esac

# (((
case $RL_MAJOR in
[[0-9][0-9]])	_RL_MAJOR=$RL_MAJOR ;;
[[0-9]])	_RL_MAJOR=0$RL_MAJOR ;;
*)		_RL_MAJOR=00 ;;
esac

# (((
case $RL_MINOR in
[[0-9][0-9]])	_RL_MINOR=$RL_MINOR ;;
[[0-9]])	_RL_MINOR=0$RL_MINOR ;;
*)		_RL_MINOR=00 ;;
esac

RL_VERSION="0x${_RL_MAJOR}${_RL_MINOR}"

# Readline versions greater than 4.2 have these defines in readline.h

if test $ac_cv_rl_version = '0.0' ; then
	AC_MSG_WARN([Could not test version of installed readline library.])
elif test $RL_MAJOR -gt 4 || { test $RL_MAJOR = 4 && test $RL_MINOR -gt 2 ; } ; then
	# set these for use by the caller
	RL_PREFIX=$ac_cv_rl_prefix
	RL_LIBDIR=$ac_cv_rl_libdir
	RL_INCLUDEDIR=$ac_cv_rl_includedir
	AC_MSG_RESULT($ac_cv_rl_version)
else

AC_DEFINE_UNQUOTED(RL_READLINE_VERSION, $RL_VERSION, [encoded version of the installed readline library])
AC_DEFINE_UNQUOTED(RL_VERSION_MAJOR, $RL_MAJOR, [major version of installed readline library])
AC_DEFINE_UNQUOTED(RL_VERSION_MINOR, $RL_MINOR, [minor version of installed readline library])

AC_SUBST(RL_VERSION)
AC_SUBST(RL_MAJOR)
AC_SUBST(RL_MINOR)

# set these for use by the caller
RL_PREFIX=$ac_cv_rl_prefix
RL_LIBDIR=$ac_cv_rl_libdir
RL_INCLUDEDIR=$ac_cv_rl_includedir

AC_MSG_RESULT($ac_cv_rl_version)

fi
])