AC_DEFUN([LX_ENABLE_DOC],

 [

   AC_ARG_ENABLE([doc],

 AS_HELP_STRING([--enable-doc@<:@=yes|no|full@:>@], [build the documentation (full enables internal documentation too) @<:@default=yes@:>@])

 AS_HELP_STRING([--disable-doc], [do not build the documentation]),

          [], [enable_doc=yes])

   AC_MSG_CHECKING([whether to build the documention])

   case "$enable_doc" in

     yes)

       DOXYGEN_INTERNAL_DOCS=NO

       AC_MSG_RESULT([yes])

       ;;

     full)

       DOXYGEN_INTERNAL_DOCS=YES

       AC_MSG_RESULT([full])

       ;;

     no)

       DOXYGEN_INTERNAL_DOCS=NO

       AC_MSG_RESULT([no])

       ;;

     *)

       AC_MSG_ERROR([bad value $enable_doc for option --enable-doc])

       ;;

   esac

   AC_SUBST(DOXYGEN_INTERNAL_DOCS)

   AM_CONDITIONAL([WANT_DOC], [test x"$enable_doc" != x"no"])

 ])