dnl $Id$

dnl Check for sys/tree.h and if it is recent enough by looking at a certain
dnl macro. Defines HAVE_SYS_TREE_H if all conditions are met.

dnl Copyright (c) 2008 Moritz Grimm <mgrimm@mrsserver.net>
dnl
dnl Permission to use, copy, modify, and distribute this software for any
dnl purpose with or without fee is hereby granted, provided that the above
dnl copyright notice and this permission notice appear in all copies.
dnl
dnl THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
dnl WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
dnl MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
dnl ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
dnl WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
dnl ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
dnl OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

dnl AX_HEADER_TREE([REQUIRED-MACRO], [ACTION-IF-FOUND],
dnl 	[ACTION-IF-NOT-FOUND])

AC_DEFUN([AX_HEADER_TREE],
[
if test x"$1" = "x"; then
	_tree_macro="RB_INIT"
else
	_tree_macro=$1
fi
AC_MSG_CHECKING([for ${_tree_macro} in sys/tree.h])
AC_CACHE_VAL([local_cv_header_sys_tree_h],
[
	AC_COMPILE_IFELSE(
		[AC_LANG_PROGRAM(
		[[
		  #include <sys/tree.h>
		  #if !defined(${_tree_macro})
		  # error Required tree macro missing
		  #endif /* !${_tree_macro} */
		]],
		[[]])],
		[local_cv_header_sys_tree_h=yes],
		[local_cv_header_sys_tree_h=no])
])
if test x"${local_cv_header_sys_tree_h}" = "xyes"; then
	AC_MSG_RESULT([yes])
	AC_DEFINE([HAVE_SYS_TREE_H], [1],
		[Define to 1 if you have a sufficiently recent <sys/tree.h> header.])
	:
	$2
else
	AC_MSG_RESULT([no])
	:
	$3
fi
])