I did some archeology, and found CheckTokenMembership() in MinGW's w32api packages version 3.14 (https://sourceforge.net/projects/mingw/files/MinGW/Base/w32api/w32api-3.14/, in include/winbase.h). According to the timestamps on that download page, that was released in 2009. That was the oldest version I could find, so it might go even further back.
Dave, do you know exactly what version of MinGW narwhal is running? And how difficult is it to upgrade to something slightly more modern? Ease of upgrade is another good data point on how far we need to support old versions.
Given that this was backpatched and that it broke narwhal in all branches, I think the solution needs to make narwhal work again without requiring it to upgrade; so we should acquire CheckTokenMembership via dynloading just like we do the other functions. If we want to require a newer mingw version in pg10, that's acceptable, but it should be a separate patch.
+1 for not moving the minimum system requirements in the back-branches.
Ok. I reverted this patch in the back-branches, and applied the much less invasive "V2" patch [1] instead. HEAD is unchanged, so narwhal still fails there.
Dave: the consensus is that we no longer support the old version of MinGW that narwhal is using, for PostgreSQL v 10. Can you modify the configuration of narwhal to not try building 'master' anymore, or upgrade the toolchain, please?
