cares-functions.m4

      AC_LANG_PROGRAM([[
        $cares_includes_winsock2
        $cares_includes_sys_socket
      ]],[[
        if(0 != setsockopt(0, SOL_SOCKET, SO_NONBLOCK, 0, 0))
          return 1;
      ]])
    ],[
      AC_MSG_RESULT([yes])
      tst_compi_setsockopt_so_nonblock="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_compi_setsockopt_so_nonblock="no"
    ])
  fi
  #
  if test "$tst_compi_setsockopt_so_nonblock" = "yes"; then
    AC_MSG_CHECKING([if setsockopt SO_NONBLOCK usage allowed])
    if test "x$cares_disallow_setsockopt_so_nonblock" != "xyes"; then
      AC_MSG_RESULT([yes])
      tst_allow_setsockopt_so_nonblock="yes"
    else
      AC_MSG_RESULT([no])
      tst_allow_setsockopt_so_nonblock="no"
    fi
  fi
  #
  AC_MSG_CHECKING([if setsockopt SO_NONBLOCK might be used])
  if test "$tst_compi_setsockopt_so_nonblock" = "yes" &&
     test "$tst_allow_setsockopt_so_nonblock" = "yes"; then
    AC_MSG_RESULT([yes])
    AC_DEFINE_UNQUOTED(HAVE_SETSOCKOPT_SO_NONBLOCK, 1,
      [Define to 1 if you have a working setsockopt SO_NONBLOCK function.])
    ac_cv_func_setsockopt_so_nonblock="yes"
  else
    AC_MSG_RESULT([no])
    ac_cv_func_setsockopt_so_nonblock="no"
  fi
])


dnl CARES_CHECK_FUNC_STRCASECMP
dnl -------------------------------------------------
dnl Verify if strcasecmp is available, prototyped, and
dnl can be compiled. If all of these are true, and
dnl usage has not been previously disallowed with
dnl shell variable cares_disallow_strcasecmp, then
dnl HAVE_STRCASECMP will be defined.

AC_DEFUN([CARES_CHECK_FUNC_STRCASECMP], [
  AC_REQUIRE([CARES_INCLUDES_STRING])dnl
  #
  tst_links_strcasecmp="unknown"
  tst_proto_strcasecmp="unknown"
  tst_compi_strcasecmp="unknown"
  tst_allow_strcasecmp="unknown"
  #
  AC_MSG_CHECKING([if strcasecmp can be linked])
  AC_LINK_IFELSE([
    AC_LANG_FUNC_LINK_TRY([strcasecmp])
  ],[
    AC_MSG_RESULT([yes])
    tst_links_strcasecmp="yes"
  ],[
    AC_MSG_RESULT([no])
    tst_links_strcasecmp="no"
  ])
  #
  if test "$tst_links_strcasecmp" = "yes"; then
    AC_MSG_CHECKING([if strcasecmp is prototyped])
    AC_EGREP_CPP([strcasecmp],[
      $cares_includes_string
    ],[
      AC_MSG_RESULT([yes])
      tst_proto_strcasecmp="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_proto_strcasecmp="no"
    ])
  fi
  #
  if test "$tst_proto_strcasecmp" = "yes"; then
    AC_MSG_CHECKING([if strcasecmp is compilable])
    AC_COMPILE_IFELSE([
      AC_LANG_PROGRAM([[
        $cares_includes_string
      ]],[[
        if(0 != strcasecmp(0, 0))
          return 1;
      ]])
    ],[
      AC_MSG_RESULT([yes])
      tst_compi_strcasecmp="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_compi_strcasecmp="no"
    ])
  fi
  #
  if test "$tst_compi_strcasecmp" = "yes"; then
    AC_MSG_CHECKING([if strcasecmp usage allowed])
    if test "x$cares_disallow_strcasecmp" != "xyes"; then
      AC_MSG_RESULT([yes])
      tst_allow_strcasecmp="yes"
    else
      AC_MSG_RESULT([no])
      tst_allow_strcasecmp="no"
    fi
  fi
  #
  AC_MSG_CHECKING([if strcasecmp might be used])
  if test "$tst_links_strcasecmp" = "yes" &&
     test "$tst_proto_strcasecmp" = "yes" &&
     test "$tst_compi_strcasecmp" = "yes" &&
     test "$tst_allow_strcasecmp" = "yes"; then
    AC_MSG_RESULT([yes])
    AC_DEFINE_UNQUOTED(HAVE_STRCASECMP, 1,
      [Define to 1 if you have the strcasecmp function.])
    ac_cv_func_strcasecmp="yes"
  else
    AC_MSG_RESULT([no])
    ac_cv_func_strcasecmp="no"
  fi
])


dnl CARES_CHECK_FUNC_STRCMPI
dnl -------------------------------------------------
dnl Verify if strcmpi is available, prototyped, and
dnl can be compiled. If all of these are true, and
dnl usage has not been previously disallowed with
dnl shell variable cares_disallow_strcmpi, then
dnl HAVE_STRCMPI will be defined.

AC_DEFUN([CARES_CHECK_FUNC_STRCMPI], [
  AC_REQUIRE([CARES_INCLUDES_STRING])dnl
  #
  tst_links_strcmpi="unknown"
  tst_proto_strcmpi="unknown"
  tst_compi_strcmpi="unknown"
  tst_allow_strcmpi="unknown"
  #
  AC_MSG_CHECKING([if strcmpi can be linked])
  AC_LINK_IFELSE([
    AC_LANG_FUNC_LINK_TRY([strcmpi])
  ],[
    AC_MSG_RESULT([yes])
    tst_links_strcmpi="yes"
  ],[
    AC_MSG_RESULT([no])
    tst_links_strcmpi="no"
  ])
  #
  if test "$tst_links_strcmpi" = "yes"; then
    AC_MSG_CHECKING([if strcmpi is prototyped])
    AC_EGREP_CPP([strcmpi],[
      $cares_includes_string
    ],[
      AC_MSG_RESULT([yes])
      tst_proto_strcmpi="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_proto_strcmpi="no"
    ])
  fi
  #
  if test "$tst_proto_strcmpi" = "yes"; then
    AC_MSG_CHECKING([if strcmpi is compilable])
    AC_COMPILE_IFELSE([
      AC_LANG_PROGRAM([[
        $cares_includes_string
      ]],[[
        if(0 != strcmpi(0, 0))
          return 1;
      ]])
    ],[
      AC_MSG_RESULT([yes])
      tst_compi_strcmpi="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_compi_strcmpi="no"
    ])
  fi
  #
  if test "$tst_compi_strcmpi" = "yes"; then
    AC_MSG_CHECKING([if strcmpi usage allowed])
    if test "x$cares_disallow_strcmpi" != "xyes"; then
      AC_MSG_RESULT([yes])
      tst_allow_strcmpi="yes"
    else
      AC_MSG_RESULT([no])
      tst_allow_strcmpi="no"
    fi
  fi
  #
  AC_MSG_CHECKING([if strcmpi might be used])
  if test "$tst_links_strcmpi" = "yes" &&
     test "$tst_proto_strcmpi" = "yes" &&
     test "$tst_compi_strcmpi" = "yes" &&
     test "$tst_allow_strcmpi" = "yes"; then
    AC_MSG_RESULT([yes])
    AC_DEFINE_UNQUOTED(HAVE_STRCMPI, 1,
      [Define to 1 if you have the strcmpi function.])
    ac_cv_func_strcmpi="yes"
  else
    AC_MSG_RESULT([no])
    ac_cv_func_strcmpi="no"
  fi
])


dnl CARES_CHECK_FUNC_STRDUP
dnl -------------------------------------------------
dnl Verify if strdup is available, prototyped, and
dnl can be compiled. If all of these are true, and
dnl usage has not been previously disallowed with
dnl shell variable cares_disallow_strdup, then
dnl HAVE_STRDUP will be defined.

AC_DEFUN([CARES_CHECK_FUNC_STRDUP], [
  AC_REQUIRE([CARES_INCLUDES_STRING])dnl
  #
  tst_links_strdup="unknown"
  tst_proto_strdup="unknown"
  tst_compi_strdup="unknown"
  tst_allow_strdup="unknown"
  #
  AC_MSG_CHECKING([if strdup can be linked])
  AC_LINK_IFELSE([
    AC_LANG_FUNC_LINK_TRY([strdup])
  ],[
    AC_MSG_RESULT([yes])
    tst_links_strdup="yes"
  ],[
    AC_MSG_RESULT([no])
    tst_links_strdup="no"
  ])
  #
  if test "$tst_links_strdup" = "yes"; then
    AC_MSG_CHECKING([if strdup is prototyped])
    AC_EGREP_CPP([strdup],[
      $cares_includes_string
    ],[
      AC_MSG_RESULT([yes])
      tst_proto_strdup="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_proto_strdup="no"
    ])
  fi
  #
  if test "$tst_proto_strdup" = "yes"; then
    AC_MSG_CHECKING([if strdup is compilable])
    AC_COMPILE_IFELSE([
      AC_LANG_PROGRAM([[
        $cares_includes_string
      ]],[[
        if(0 != strdup(0))
          return 1;
      ]])
    ],[
      AC_MSG_RESULT([yes])
      tst_compi_strdup="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_compi_strdup="no"
    ])
  fi
  #
  if test "$tst_compi_strdup" = "yes"; then
    AC_MSG_CHECKING([if strdup usage allowed])
    if test "x$cares_disallow_strdup" != "xyes"; then
      AC_MSG_RESULT([yes])
      tst_allow_strdup="yes"
    else
      AC_MSG_RESULT([no])
      tst_allow_strdup="no"
    fi
  fi
  #
  AC_MSG_CHECKING([if strdup might be used])
  if test "$tst_links_strdup" = "yes" &&
     test "$tst_proto_strdup" = "yes" &&
     test "$tst_compi_strdup" = "yes" &&
     test "$tst_allow_strdup" = "yes"; then
    AC_MSG_RESULT([yes])
    AC_DEFINE_UNQUOTED(HAVE_STRDUP, 1,
      [Define to 1 if you have the strdup function.])
    ac_cv_func_strdup="yes"
  else
    AC_MSG_RESULT([no])
    ac_cv_func_strdup="no"
  fi
])


dnl CARES_CHECK_FUNC_STRICMP
dnl -------------------------------------------------
dnl Verify if stricmp is available, prototyped, and
dnl can be compiled. If all of these are true, and
dnl usage has not been previously disallowed with
dnl shell variable cares_disallow_stricmp, then
dnl HAVE_STRICMP will be defined.

AC_DEFUN([CARES_CHECK_FUNC_STRICMP], [
  AC_REQUIRE([CARES_INCLUDES_STRING])dnl
  #
  tst_links_stricmp="unknown"
  tst_proto_stricmp="unknown"
  tst_compi_stricmp="unknown"
  tst_allow_stricmp="unknown"
  #
  AC_MSG_CHECKING([if stricmp can be linked])
  AC_LINK_IFELSE([
    AC_LANG_FUNC_LINK_TRY([stricmp])
  ],[
    AC_MSG_RESULT([yes])
    tst_links_stricmp="yes"
  ],[
    AC_MSG_RESULT([no])
    tst_links_stricmp="no"
  ])
  #
  if test "$tst_links_stricmp" = "yes"; then
    AC_MSG_CHECKING([if stricmp is prototyped])
    AC_EGREP_CPP([stricmp],[
      $cares_includes_string
    ],[
      AC_MSG_RESULT([yes])
      tst_proto_stricmp="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_proto_stricmp="no"
    ])
  fi
  #
  if test "$tst_proto_stricmp" = "yes"; then
    AC_MSG_CHECKING([if stricmp is compilable])
    AC_COMPILE_IFELSE([
      AC_LANG_PROGRAM([[
        $cares_includes_string
      ]],[[
        if(0 != stricmp(0, 0))
          return 1;
      ]])
    ],[
      AC_MSG_RESULT([yes])
      tst_compi_stricmp="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_compi_stricmp="no"
    ])
  fi
  #
  if test "$tst_compi_stricmp" = "yes"; then
    AC_MSG_CHECKING([if stricmp usage allowed])
    if test "x$cares_disallow_stricmp" != "xyes"; then
      AC_MSG_RESULT([yes])
      tst_allow_stricmp="yes"
    else
      AC_MSG_RESULT([no])
      tst_allow_stricmp="no"
    fi
  fi
  #
  AC_MSG_CHECKING([if stricmp might be used])
  if test "$tst_links_stricmp" = "yes" &&
     test "$tst_proto_stricmp" = "yes" &&
     test "$tst_compi_stricmp" = "yes" &&
     test "$tst_allow_stricmp" = "yes"; then
    AC_MSG_RESULT([yes])
    AC_DEFINE_UNQUOTED(HAVE_STRICMP, 1,
      [Define to 1 if you have the stricmp function.])
    ac_cv_func_stricmp="yes"
  else
    AC_MSG_RESULT([no])
    ac_cv_func_stricmp="no"
  fi
])


dnl CARES_CHECK_FUNC_STRNCASECMP
dnl -------------------------------------------------
dnl Verify if strncasecmp is available, prototyped, and
dnl can be compiled. If all of these are true, and
dnl usage has not been previously disallowed with
dnl shell variable cares_disallow_strncasecmp, then
dnl HAVE_STRNCASECMP will be defined.

AC_DEFUN([CARES_CHECK_FUNC_STRNCASECMP], [
  AC_REQUIRE([CARES_INCLUDES_STRING])dnl
  #
  tst_links_strncasecmp="unknown"
  tst_proto_strncasecmp="unknown"
  tst_compi_strncasecmp="unknown"
  tst_allow_strncasecmp="unknown"
  #
  AC_MSG_CHECKING([if strncasecmp can be linked])
  AC_LINK_IFELSE([
    AC_LANG_FUNC_LINK_TRY([strncasecmp])
  ],[
    AC_MSG_RESULT([yes])
    tst_links_strncasecmp="yes"
  ],[
    AC_MSG_RESULT([no])
    tst_links_strncasecmp="no"
  ])
  #
  if test "$tst_links_strncasecmp" = "yes"; then
    AC_MSG_CHECKING([if strncasecmp is prototyped])
    AC_EGREP_CPP([strncasecmp],[
      $cares_includes_string
    ],[
      AC_MSG_RESULT([yes])
      tst_proto_strncasecmp="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_proto_strncasecmp="no"
    ])
  fi
  #
  if test "$tst_proto_strncasecmp" = "yes"; then
    AC_MSG_CHECKING([if strncasecmp is compilable])
    AC_COMPILE_IFELSE([
      AC_LANG_PROGRAM([[
        $cares_includes_string
      ]],[[
        if(0 != strncasecmp(0, 0, 0))
          return 1;
      ]])
    ],[
      AC_MSG_RESULT([yes])
      tst_compi_strncasecmp="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_compi_strncasecmp="no"
    ])
  fi
  #
  if test "$tst_compi_strncasecmp" = "yes"; then
    AC_MSG_CHECKING([if strncasecmp usage allowed])
    if test "x$cares_disallow_strncasecmp" != "xyes"; then
      AC_MSG_RESULT([yes])
      tst_allow_strncasecmp="yes"
    else
      AC_MSG_RESULT([no])
      tst_allow_strncasecmp="no"
    fi
  fi
  #
  AC_MSG_CHECKING([if strncasecmp might be used])
  if test "$tst_links_strncasecmp" = "yes" &&
     test "$tst_proto_strncasecmp" = "yes" &&
     test "$tst_compi_strncasecmp" = "yes" &&
     test "$tst_allow_strncasecmp" = "yes"; then
    AC_MSG_RESULT([yes])
    AC_DEFINE_UNQUOTED(HAVE_STRNCASECMP, 1,
      [Define to 1 if you have the strncasecmp function.])
    ac_cv_func_strncasecmp="yes"
  else
    AC_MSG_RESULT([no])
    ac_cv_func_strncasecmp="no"
  fi
])


dnl CARES_CHECK_FUNC_STRNCMPI
dnl -------------------------------------------------
dnl Verify if strncmpi is available, prototyped, and
dnl can be compiled. If all of these are true, and
dnl usage has not been previously disallowed with
dnl shell variable cares_disallow_strncmpi, then
dnl HAVE_STRNCMPI will be defined.

AC_DEFUN([CARES_CHECK_FUNC_STRNCMPI], [
  AC_REQUIRE([CARES_INCLUDES_STRING])dnl
  #
  tst_links_strncmpi="unknown"
  tst_proto_strncmpi="unknown"
  tst_compi_strncmpi="unknown"
  tst_allow_strncmpi="unknown"
  #
  AC_MSG_CHECKING([if strncmpi can be linked])
  AC_LINK_IFELSE([
    AC_LANG_FUNC_LINK_TRY([strncmpi])
  ],[
    AC_MSG_RESULT([yes])
    tst_links_strncmpi="yes"
  ],[
    AC_MSG_RESULT([no])
    tst_links_strncmpi="no"
  ])
  #
  if test "$tst_links_strncmpi" = "yes"; then
    AC_MSG_CHECKING([if strncmpi is prototyped])
    AC_EGREP_CPP([strncmpi],[
      $cares_includes_string
    ],[
      AC_MSG_RESULT([yes])
      tst_proto_strncmpi="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_proto_strncmpi="no"
    ])
  fi
  #
  if test "$tst_proto_strncmpi" = "yes"; then
    AC_MSG_CHECKING([if strncmpi is compilable])
    AC_COMPILE_IFELSE([
      AC_LANG_PROGRAM([[
        $cares_includes_string
      ]],[[
        if(0 != strncmpi(0, 0))
          return 1;
      ]])
    ],[
      AC_MSG_RESULT([yes])
      tst_compi_strncmpi="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_compi_strncmpi="no"
    ])
  fi
  #
  if test "$tst_compi_strncmpi" = "yes"; then
    AC_MSG_CHECKING([if strncmpi usage allowed])
    if test "x$cares_disallow_strncmpi" != "xyes"; then
      AC_MSG_RESULT([yes])
      tst_allow_strncmpi="yes"
    else
      AC_MSG_RESULT([no])
      tst_allow_strncmpi="no"
    fi
  fi
  #
  AC_MSG_CHECKING([if strncmpi might be used])
  if test "$tst_links_strncmpi" = "yes" &&
     test "$tst_proto_strncmpi" = "yes" &&
     test "$tst_compi_strncmpi" = "yes" &&
     test "$tst_allow_strncmpi" = "yes"; then
    AC_MSG_RESULT([yes])
    AC_DEFINE_UNQUOTED(HAVE_STRNCMPI, 1,
      [Define to 1 if you have the strncmpi function.])
    ac_cv_func_strncmpi="yes"
  else
    AC_MSG_RESULT([no])
    ac_cv_func_strncmpi="no"
  fi
])


dnl CARES_CHECK_FUNC_STRNICMP
dnl -------------------------------------------------
dnl Verify if strnicmp is available, prototyped, and
dnl can be compiled. If all of these are true, and
dnl usage has not been previously disallowed with
dnl shell variable cares_disallow_strnicmp, then
dnl HAVE_STRNICMP will be defined.

AC_DEFUN([CARES_CHECK_FUNC_STRNICMP], [
  AC_REQUIRE([CARES_INCLUDES_STRING])dnl
  #
  tst_links_strnicmp="unknown"
  tst_proto_strnicmp="unknown"
  tst_compi_strnicmp="unknown"
  tst_allow_strnicmp="unknown"
  #
  AC_MSG_CHECKING([if strnicmp can be linked])
  AC_LINK_IFELSE([
    AC_LANG_FUNC_LINK_TRY([strnicmp])
  ],[
    AC_MSG_RESULT([yes])
    tst_links_strnicmp="yes"
  ],[
    AC_MSG_RESULT([no])
    tst_links_strnicmp="no"
  ])
  #
  if test "$tst_links_strnicmp" = "yes"; then
    AC_MSG_CHECKING([if strnicmp is prototyped])
    AC_EGREP_CPP([strnicmp],[
      $cares_includes_string
    ],[
      AC_MSG_RESULT([yes])
      tst_proto_strnicmp="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_proto_strnicmp="no"
    ])
  fi
  #
  if test "$tst_proto_strnicmp" = "yes"; then
    AC_MSG_CHECKING([if strnicmp is compilable])
    AC_COMPILE_IFELSE([
      AC_LANG_PROGRAM([[
        $cares_includes_string
      ]],[[
        if(0 != strnicmp(0, 0))
          return 1;
      ]])
    ],[
      AC_MSG_RESULT([yes])
      tst_compi_strnicmp="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_compi_strnicmp="no"
    ])
  fi
  #
  if test "$tst_compi_strnicmp" = "yes"; then
    AC_MSG_CHECKING([if strnicmp usage allowed])
    if test "x$cares_disallow_strnicmp" != "xyes"; then
      AC_MSG_RESULT([yes])
      tst_allow_strnicmp="yes"
    else
      AC_MSG_RESULT([no])
      tst_allow_strnicmp="no"
    fi
  fi
  #
  AC_MSG_CHECKING([if strnicmp might be used])
  if test "$tst_links_strnicmp" = "yes" &&
     test "$tst_proto_strnicmp" = "yes" &&
     test "$tst_compi_strnicmp" = "yes" &&
     test "$tst_allow_strnicmp" = "yes"; then
    AC_MSG_RESULT([yes])
    AC_DEFINE_UNQUOTED(HAVE_STRNICMP, 1,
      [Define to 1 if you have the strnicmp function.])
    ac_cv_func_strnicmp="yes"
  else
    AC_MSG_RESULT([no])
    ac_cv_func_strnicmp="no"
  fi
])


dnl CARES_CHECK_FUNC_WRITEV
dnl -------------------------------------------------
dnl Verify if writev is available, prototyped, and
dnl can be compiled. If all of these are true, and
dnl usage has not been previously disallowed with
dnl shell variable cares_disallow_writev, then
dnl HAVE_WRITEV will be defined.

AC_DEFUN([CARES_CHECK_FUNC_WRITEV], [
  AC_REQUIRE([CARES_INCLUDES_SYS_UIO])dnl
  #
  tst_links_writev="unknown"
  tst_proto_writev="unknown"
  tst_compi_writev="unknown"
  tst_allow_writev="unknown"
  #
  AC_MSG_CHECKING([if writev can be linked])
  AC_LINK_IFELSE([
    AC_LANG_FUNC_LINK_TRY([writev])
  ],[
    AC_MSG_RESULT([yes])
    tst_links_writev="yes"
  ],[
    AC_MSG_RESULT([no])
    tst_links_writev="no"
  ])
  #
  if test "$tst_links_writev" = "yes"; then
    AC_MSG_CHECKING([if writev is prototyped])
    AC_EGREP_CPP([writev],[
      $cares_includes_sys_uio
    ],[
      AC_MSG_RESULT([yes])
      tst_proto_writev="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_proto_writev="no"
    ])
  fi
  #
  if test "$tst_proto_writev" = "yes"; then
    AC_MSG_CHECKING([if writev is compilable])
    AC_COMPILE_IFELSE([
      AC_LANG_PROGRAM([[
        $cares_includes_sys_uio
      ]],[[
        if(0 != writev(0, 0, 0))
          return 1;
      ]])
    ],[
      AC_MSG_RESULT([yes])
      tst_compi_writev="yes"
    ],[
      AC_MSG_RESULT([no])
      tst_compi_writev="no"
    ])
  fi
  #
  if test "$tst_compi_writev" = "yes"; then
    AC_MSG_CHECKING([if writev usage allowed])
    if test "x$cares_disallow_writev" != "xyes"; then
      AC_MSG_RESULT([yes])
      tst_allow_writev="yes"
    else
      AC_MSG_RESULT([no])
      tst_allow_writev="no"
    fi
  fi
  #
  AC_MSG_CHECKING([if writev might be used])
  if test "$tst_links_writev" = "yes" &&
     test "$tst_proto_writev" = "yes" &&
     test "$tst_compi_writev" = "yes" &&
     test "$tst_allow_writev" = "yes"; then
    AC_MSG_RESULT([yes])
    AC_DEFINE_UNQUOTED(HAVE_WRITEV, 1,
      [Define to 1 if you have the writev function.])
    ac_cv_func_writev="yes"
  else
    AC_MSG_RESULT([no])
    ac_cv_func_writev="no"
  fi
])