I wrote: > Sergey Shinderuk <s.shinde...@postgrespro.ru> writes: >>>> note: 'pwritev' has been marked as being introduced in macOS 11.0 here, >>>> but the deployment target is macOS 10.15.0
> The symptoms sound consistent with using bleeding-edge Xcode on a > Catalina machine ... please report exact OS and Xcode versions. I can reproduce these warnings on Big Sur + Xcode 12.3 by doing export MACOSX_DEPLOYMENT_TARGET=10.15 before building; however the executable runs anyway, which I guess is unsurprising. AFAICS from config.log, configure has no idea that anything is wrong. (BTW, at least the rather-old version of ccache I'm using does not seem to realize that that environment variable is significant; I had to clear ~/.ccache to get consistent results.) We've had issues before with weird results from Xcode versions newer than the underlying OS. In the past we've been able to work around that, but I'm not sure that I see a way here. regards, tom lane