How do I compile Apple's Security framework?
This ended up being a lot more complicated than I think rightly fits this site's Q&amp;A format. Even so, I didn't want to leave this question hanging, since I did get the framework to build, kindda.
This repository should build fully in 10.9.5 running the latest compatible version of xCode, and using the 10.9 SDK. https://github.com/Wowfunhappy/Wowfunhappy-Mavericks-Security-Framework
I used the &quot;User Framework Search Paths&quot; to add libraries, but because it's an absolute rather than a relative path, you may need to update it on your machine. This should be trivial even if it is a bit tedious—all of the actual frameworks are included in the Git repository. These Frameworks come from a combination of opensource.apple.com (preferred wherever available for obvious reasons), samdmarshall's reverse-engineered private SDK, and the Darling project.
The built Framework does not appear to actually function—replacing it on my hard drive makes the computer (a VM, thankfully) unable to boot. I initially expected this to be a code signing issue, but it doesn't look like that's the problem. But, still, it built!
tl;dr I wasn't making some stupid oversight, Apple's opensource releases are basically impossible to actually build without additional reverse engineering. Luckily, that reverse engineering work has largely been done by various projects, but seemingly not to the point where you can build something that actually works.