I had one problem during building application in the recent Xcode 5.1. Compilation fails with \"Undefined symbols for architecture x86_64\" error.
I build my project wit
I had same problem yesterday and I was finally able to build with 64-bit simulator.
After the link you tried, I replaced the library and all the header files. but it wasn't enough. Then I also unlink the libzbar.a from Link Binary With Libraries on Bulid Phases and re-add the library. Then it was working.
Let me know if it works for you.