cannot use TOR_PT_EXIT_ON_STDIN_CLOSE with meek-client-torbrowser

I am using meek built from the 0.28 tag on macOS.

If I add TOR_PT_EXIT_ON_STDIN_CLOSE=1 to the environment and start meek-client-torbrowser, the meek-client process that is started exits immediately. It generates this message on its way out: synthesizing SIGTERM because of stdin close I think this happens because meek-client-torbrowser does not attach stdin to anything when starting meek-client.

I am not sure how best to fix this. One approach would be for meek-client-torbrowser to remove TOR_PT_EXIT_ON_STDIN_CLOSE=1 from the environmnt before starting meek-client (since meek-client-torbrowser already handles TOR_PT_EXIT_ON_STDIN_CLOSE=1 on its own).