[kps]

I don't work for Apple and have never seen Xcode source, but my guess (based on what I would do) would be that Xcode invokes Clang/LLVM as libraries rather than a standalone binary, in order to keep persistent state. In principle GCC could present such an interface, but in practice FSF policies prevent it. The point is that the static analysis can be used directly or by other tools (there is a web interface, for instance); it is not restricted to Xcode.

[jordigh]

So... it's not apparently possible without modifying the source code. So like I said originally, what Xcode is using for static analysis is apparently Apple's choice, not yours nor mine.

[kps]

Yes; what's the point? Nobody's making you use Xcode (I don't), and nobody's stopping you using the Clang/LLVM features like static analysis outside of Xcode. If you want, you're free to call clang's static analysis from GNUstep's Xcode clone¹ (assuming GNUstep's license allows that; LLVM's certainly does), or any other IDE or editor.

¹https://github.com/gnustep/gnustep-xcode