AC_DEFUN([AG_WITHLIB_GUILE],[
  AC_ARG_WITH([libguile],
    AC_HELP_STRING([--with-libguile], [libguile installation prefix]),
    [ag_cv_with_libguile_root=${with_libguile}],
    AC_CACHE_CHECK([whether with-libguile was specified], ag_cv_with_libguile_root,
      ag_cv_with_libguile_root=no)
  ) # end of AC_ARG_WITH libguile

  if test "${with_libguile+set}" = set && \
     test "${withval}" = no
  then ## disabled by request
    ag_cv_with_libguile_root=no
    ag_cv_with_libguile_cflags=no
    ag_cv_with_libguile_libs=no
  else

  AC_ARG_WITH([libguile-cflags],
    AC_HELP_STRING([--with-libguile-cflags], [libguile compile flags]),
    [ag_cv_with_libguile_cflags=${with_guile_cflags}],
    AC_CACHE_CHECK([whether with-libguile-cflags was specified], ag_cv_with_libguile_cflags,
      ag_cv_with_libguile_cflags=no)
  ) # end of AC_ARG_WITH libguile-cflags

  AC_ARG_WITH([libguile-libs],
    AC_HELP_STRING([--with-libguile-libs], [libguile link command arguments]),
    [ag_cv_with_libguile_libs=${with_guile_libs}],
    AC_CACHE_CHECK([whether with-libguile-libs was specified], ag_cv_with_libguile_libs,
      ag_cv_with_libguile_libs=no)
  ) # end of AC_ARG_WITH libguile-libs

  case "X${ag_cv_with_libguile_cflags}" in
  Xyes|Xno|X )
    case "X${ag_cv_with_libguile_root}" in
    Xyes|Xno|X ) ag_cv_with_libguile_cflags=no ;;
    * )        ag_cv_with_libguile_cflags=-I${ag_cv_with_libguile_root}/include ;;
    esac
  esac
  case "X${ag_cv_with_libguile_libs}" in
  Xyes|Xno|X )
    case "X${ag_cv_with_libguile_root}" in
    Xyes|Xno|X ) ag_cv_with_libguile_libs=no ;;
    * )        ag_cv_with_libguile_libs="-L${ag_cv_with_libguile_root}/lib -lguile";;
    esac
  esac
  ag_save_CPPFLAGS="${CPPFLAGS}"
  ag_save_LIBS="${LIBS}"
  case "X${ag_cv_with_libguile_cflags}" in
  Xyes|Xno|X )
    f=`guile-config compile 2>/dev/null` || f=''
    test -n "${f}" && ag_cv_with_libguile_cflags="${f}" && \
      AC_MSG_NOTICE([guile-config used for CFLAGS: $f]) ;;
  esac
  case "X${ag_cv_with_libguile_libs}" in
  Xyes|Xno|X )
    f=`guile-config link 2>/dev/null` || f=''
    test -n "${f}" && ag_cv_with_libguile_libs="${f}" && \
      AC_MSG_NOTICE([guile-config used for LIBS: $f]) ;;
  esac
  fi ## disabled by request

  case "X${ag_cv_with_libguile_cflags}" in
  Xyes|Xno|X )
    ag_cv_with_libguile_cflags="" ;;
  * ) CPPFLAGS="${CPPFLAGS} ${ag_cv_with_libguile_cflags}" ;;
  esac
  case "X${ag_cv_with_libguile_libs}" in
  Xyes|Xno|X )
    LIBS="${LIBS} -lguile"
    ag_cv_with_libguile_libs="-lguile" ;;
  * )
    LIBS="${LIBS} ${ag_cv_with_libguile_libs}" ;;
  esac
  LIBGUILE_CFLAGS=""
  LIBGUILE_LIBS=""
  AC_MSG_CHECKING([whether libguile can be linked with])
  AC_CACHE_VAL([ag_cv_with_libguile],[
  AC_LINK_IFELSE([[@%:@include <guile/gh.h>
@%:@include <libguile.h>
int main () {
  SCM fumble, bumble, stumble;
  stumble = scm_cons( fumble, bumble );
  stumble = scm_display( fumble, bumble );
  stumble = scm_ilength( fumble );
  stumble = scm_makstr( 1, 2 );
  stumble = gh_eval_str( "stumble" );
  scm_misc_error( "oops", "bad", bumble );
  stumble = scm_num_eq_p( fumble, bumble );
  scm_wrong_type_arg( "oops", 1, bumble );
  return 0; }]],
    [ag_cv_with_libguile=yes],
    [ag_cv_with_libguile=no]) # end of AC_LINK_IFELSE 
  ]) # end of AC_CACHE_VAL for ag_cv_with_libguile
  AC_MSG_RESULT([${ag_cv_with_libguile}])
    AC_SUBST([LIBGUILE_CFLAGS])
    AC_SUBST([LIBGUILE_LIBS])
    AC_SUBST([LIBGUILE_PATH])

  if test "X${ag_cv_with_libguile}" != Xno
  then[
      LIBGUILE_CFLAGS="${ag_cv_with_libguile_cflags}"
      LIBGUILE_LIBS="${ag_cv_with_libguile_libs}"
      case "${LIBGUILE_LIBS}" in *-L* )
        LIBGUILE_PATH=`echo ${LIBGUILE_LIBS} | sed 's/.*-L[ 	]*//;s/[ 	].*//'`
      ;; * ) LIBGUILE_PATH='' ;; esac]
      CPPFLAGS="@S|@{ag_save_CPPFLAGS}"
  LIBS="@S|@{ag_save_LIBS}"
  else
    CPPFLAGS="${ag_save_CPPFLAGS}"
    LIBS="${ag_save_LIBS}"
      LIBGUILE_CFLAGS=''
      LIBGUILE_LIBS=''
      LIBGUILE_PATH=''
      AC_MSG_ERROR([Cannot find working libguile])
  fi
  AC_SUBST([AG_GUILE])
  
]) # end of AC_DEFUN of AG_WITHLIB_GUILE


AC_DEFUN([AG_LINK_EVAL_STRING],[
  AC_MSG_CHECKING([whether scm_primitive_eval_x links])
  AC_CACHE_VAL([ag_cv_link_eval_string],[
    ag_save_CPPFLAGS="${CPPFLAGS}"
    CPPFLAGS="${ag_cv_with_libguile_cflags} ${CPPFLAGS}"
    ag_save_LIBS="${LIBS}"
    LIBS="${ag_cv_with_libguile_libs} ${LIBS}"
  AC_TRY_LINK([@%:@include <guile/gh.h>
@%:@include <libguile.h>],
    [SCM res = scm_primitive_eval_x( SCM_UNDEFINED );],
    [ag_cv_link_eval_string=yes],[ag_cv_link_eval_string=no]
  ) # end of TRY_LINK
    CPPFLAGS="${ag_save_CPPFLAGS}"
    LIBS="${ag_save_LIBS}"
  ]) # end of AC_CACHE_VAL for ag_cv_link_eval_string
  AC_MSG_RESULT([${ag_cv_link_eval_string}])

  if test "X${ag_cv_link_eval_string}" = Xno
  then
    AC_DEFINE([scm_primitive_eval_x], [scm_eval_x],
        [Define this if no scm_primitive_eval_x])
AC_DEFINE([scm_t_port], [scm_port], [Define this if no scm_t_port])
  fi
  
]) # end of AC_DEFUN of AG_LINK_EVAL_STRING