message: remove ringbuffer option.
diff: @@ -20,9 +20,6 @@ PHP_ARG_ENABLE(swoole-debug, whether to enable swoole debug,
  PHP_ARG_ENABLE(sockets, enable sockets support,
  [ --enable-sockets Do you have sockets extension?], no, no)
  -PHP_ARG_ENABLE(ringbuffer, enable ringbuffer shared memory pool support,
  -[ --enable-ringbuffer Experimental: Use ringbuffer memory pool?], no, no)
  -
  PHP_ARG_ENABLE(async_redis, enable async_redis support,
  [ --enable-async-redis Do you have hiredis?], no, no)
  @@ -183,10 +180,6 @@ if test "$PHP_SWOOLE" != "no"; then
  AC_DEFINE(SW_SOCKETS, 1, [enable sockets support])
  fi
  - if test "$PHP_RINGBUFFER" = "yes"; then
  - AC_DEFINE(SW_USE_RINGBUFFER, 1, [enable ringbuffer support])
  - fi
  -
  if test "$PHP_HTTP2" = "yes"; then
  AC_DEFINE(SW_USE_HTTP2, 1, [enable http2.0 support])
  fi
  