We have isolated it to the reactive-cocoa podfile but as far as I can tell there's nothing changed with the podspec.
Initially used the 0.16.2 version of the reactive-cocoa podspec but have tried it also with the latest 1.4.0 and get the same error.
I have the latest cocoapods from ruby gems @ version 0.16.4.
Sorry about that we have switched to new system for linting the specs which was is based on the 0.17rcs. Unfortunately this linter warned about a deprecation (now disabled) introduced in CocoaPods 0.17 which is not compatible with 0.16. It looks like somebody took it seriously and fixed the spec too soon.