Building source from external directories in Xcode 4

I have a directory of source files (.h and .m) that are shared between multiple projects. I'm not building them as a static library; instead, I just include the source in each project.

Previously, I was copying the source into each project independently, but now, I'd like to move to having a single directory that has all of those shared files it, and include a folder reference to them in each XCode project that uses them.

Including them as a folder reference (blue folder) is no problem, and I can add the path to the header includes so that the files in开发者_如何学JAVA the project can see them. But they're not being built, and thus I'm getting link errors.

How do I get Xcode to build the source in the external directory?

folder references don't work like that in xcode.

this is exactly what an external target (e.g. static library) is for... seems strange that you would choose to duplicate (a portion of) the maintenance for every project. with a library, you can also reduce the build and indexing times (assuming the build settings match some of the time).

if you insist that a static library is a bad idea... you can approximate what you want by creating a custom build script phase for your target (you will need to configure a script, rather than passing the xcode folder reference as input).