You only need MACOSX_DEPLOYMENT_TARGET / -mmacosx-version-min when building binaries to run on older mac versions. Whoever distributes cysignals should decide which min sdk version they support. What is bound to go wrong is that somebody builds an application that includes your library with their chosen MACOSX_DEPLOYMENT_TARGET, and the binaries don't work because some dependency thought it would be fun to require a higher version. And the distributor of the app (like Sage) typically doesn't have a basement full of old macs to test if the binaries really are downward compatible.
* If you definitely require <atomic> then just include it. Add a comment with the min sdk version for anyone hitting that #include error. * If <atomic> is optional then add a #warning that it is recommended -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.