CocoaPods/Specs — pull request #1987 by NSMutableString (2013-04-30 10:03:36+00:00)
Title: Update ZXing (2.1) pod spec to solve iOS sub spec issue with latest stable version (0.18.1)

This will fix the build error.
ZXing (2.1) issue with latest stable version (0.18.1)
see issue #issue 1008