Can I link agaist them anyway?
No. Well, you might be able to get it to link, and it might even work if you’re lucky, but it’s most definitely not supported. All components of a linked Mach-O image must use the same deployment target. I’ve seen some wacky and very hard-to-track-down bugs caused by folks not following that rule.
One option is to put the older libraries in their own Mach-O image (a dylib, framework, or bundle). It’s fine to have different deployment targets across image boundaries.
Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware
let myEmail = "eskimo" + "1" + "@apple.com"