I replace zBar SDK in my project and faced with the problem.
ld: file is universal (3 slices) but does not contain a(n) armv7s slice: /Volumes/ZBarSDK/ZBarSDK/libzbar.a file '/Volumes/ZBarSDK/ZBarSDK/libzbar.a' for architecture armv7s
clang: error: linker command failed with exit code 1 (use -v to see invocation)
I downloaded SDK from http://nerdvision.net/app-development/ios/zbar-sdk
P.S. In simulator it work.
You can use a custom version of ZbarSdk built for iOS 7, which can be found here : http://nerdvision.net/app-development/ios/zbar-sdk