I see. I manged to compile your commit, seems problem was with missing user, pass in proxy config.
but now different error:
[2018-08-12 03:09:51.633] ckpassthrough generator starting
[2018-08-12 03:09:51.633] ckpassthrough stratifier starting
[2018-08-12 03:09:51.633] ckpassthrough connector starting
[2018-08-12 03:09:51.634] ckpassthrough connector ready
[2018-08-12 03:09:51.634] ckpassthrough stratifier ready
[2018-08-12 03:09:51.647] Failed to increase rcvbufsiz to 1048576, increase rmem_max or start ckpassthrough privileged
[2018-08-12 03:09:51.647] Failed to increase sendbufsize to 1048576, increase wmem_max or start ckpassthrough privileged
[2018-08-12 03:09:51.649] Denied passthrough for stratum
[2018-08-12 03:09:51.649] Failed initial passthrough to localhost:3737 !
[2018-08-12 03:09:51.654] Denied passthrough for stratum
[2018-08-12 03:09:51.654] Failed initial passthrough to localhost:3737 !

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with ./ckpool -u  - similar error with auth
[2018-08-12 03:09:19.705] Proxy 0:0 localhost:3737 failed to authorise in auth_stratum, got: {"id":42,"result":false,"error":null}
[2018-08-12 03:09:19.705] Failed initial authorise to localhost:3737 with user:pass !

--
seems that ckpool binary tries to athorize rigth away, but it should probably do it on first user connect?
I try to configure some shitcoin algo maybe it's not suitable for this?

btw, can't simple proxy written it work? I mean if I only need to 'bridge' traffic?