dnl @synopsis AC_DEFINE_DIR(VARNAME, DIR [, DESCRIPTION])
dnl
dnl This macro _AC_DEFINEs VARNAME to the expansion of the DIR
dnl variable, taking care of fixing up ${prefix} and such.
dnl
dnl VARNAME is offered as both a C preprocessor symbol, and an output
dnl variable.
dnl
dnl Note that the 3 argument form is only supported with autoconf 2.13
dnl and later (i.e. only where _AC_DEFINE supports 3 arguments).
dnl
dnl Examples:
dnl
dnl    AC_DEFINE_DIR(DATADIR, datadir)
dnl    AC_DEFINE_DIR(PROG_PATH, bindir, [Location of installed binaries])
dnl
dnl @category Misc
dnl @author Stepan Kasal <kasal@ucw.cz>
dnl @author Andreas Schwab <schwab@suse.de>
dnl @author Guido Draheim <guidod@gmx.de>
dnl @author Alexandre Oliva
dnl @version 2005-01-17
dnl @license AllPermissive

AC_DEFUN([AC_DEFINE_DIR], [
  prefix_NONE=
  exec_prefix_NONE=
  test "x$prefix" = xNONE && prefix_NONE=yes && prefix=$ac_default_prefix
  test "x$exec_prefix" = xNONE && exec_prefix_NONE=yes && exec_prefix=$prefix
  eval ac_define_dir="\"[$]$2\""
  AC_SUBST($1, "$ac_define_dir")
  AC_DEFINE_UNQUOTED($1, "$ac_define_dir", [$3])
  test "$prefix_NONE" && prefix=NONE
  test "$exec_prefix_NONE" && exec_prefix=NONE
])