@shindere / @xavierleroy - would you like to update both the Cygwin workers and Jenkins to have the FlexDLL 0.39 package from Cygwin? It needs setup to be run manually so that "Test" packages can be checked. It should then automatically offer 0.39-1 as an update to the flexdll package (if it doesn't, you might need a different mirror - https://mirrorservice.org has definitely updated).

I've tested it on my machine, but it would of course be good to have trunk and 4.12 being regularly tested with a full Cygwin64 build.

I updated the Cygwin64 worker with FlexDLL 0.39-1. Maybe we can keep the old FlexDLL on the Cygwin32 worker for a bit longer? As to "updating Jenkins to have FlexDLL" I don't know what that means.

Sorry, I don’t know if it was “damn you autocorrect” or just Friday madness but I meant on Jenkins, not and Jenkins!

So, Jenkins ran the testsuite on Cygwin64 and there's a handful of errors like

>      14 [main] ocamlrun 10122 child_info_fork::abort: address space needed by 'dllunix.so' (0x440000) is already occupied
> Fatal error: exception Unix.Unix_error(Unix.EAGAIN, "create_process", "/bin/sh")

It also happens when calling Unix.fork().

I'm afraid this is not the end of the Cygwin64 story...

That's strange, given that the DLL should never have a base address that low. I'll have a look - we're at least now in the realm of Cygwin64 not working, rather than FlexDLL!

I may have botched the Cygwin upgrade (or upgraded the wrong machine...). Let me try again.

After a proper upgrade of the Cygwin64 host, CI succeds! Happy end for a long story. Thanks for all the efforts.