Fix bash script bug for macOS, eventhough we don't support it.
Fix bash script bug for macOS, eventhough we don't support it.

winlinvip/srs,winlinvip/srs,winlinvip/srs,ossrs/srs,winlinvip/srs,ossrs/srs,ossrs/srs,winlinvip/srs,ossrs/srs,ossrs/srs,ossrs/srs,winlinvip/simple-rtmp-server,winlinvip/srs