Static library with ARC support linked to non-ARC project causing linker errors

I assumed that the toolchain may have added the necessary libraries to link to, in order for ARC to work properly. So the linker transcript may contain this piece of information. If the project of the app itself is not ARC-enabled, you may not get these by default, but you could still link to them by defining them explicitly.

Looking at the build transcript you can indeed find the appropriate linker flag there: it’s called -fobjc-arc (just as the related compiler flag). When you add this setting to Other Linker Flags, the linker will include the ARC library with the main build product and the code should run fine.

I'm adding a new answer to this as the previous accepted solution no longer appears to work with Xcode 4.3.2. I can only assume that the -fobjc-arc linker flag was never supposed to be exposed and has now been removed.

This appears to be a known issue although the only thread I can find on this with somebody from Apple commenting on the devforums dates back to mid-2011. From that thread, it is suggested that manually linking the following file solves the issue:

${DEVROOT}/Platforms/iPhoneOS.platform/Developer/usr/lib/arc/libarclite_iphoneos.a

This requires you to be compiling using the latest compiler/SDK though. I'm submitting this answer without testing, please upvote if it works, downvote if it doesn't!