I\'m getting this error
error: Invalid bitcode signature
clang: error: linker command failed with exit code 1 (use -v to see invocation)
I was having this problem since adding Cocoapods (actually added to start using ResearchKit).
I had gone through and ensured bitcode enabled was set to NO, but thought it odd that the 'Pods' project (within the project workspace) didn't have a definition for 'Bitcode Enabled' under Build Settings. After lots of frustration, I tried adding the 'Bitcode Enabled' setting for the ResearchKit project (I just cut&pasted the key/values from my main app project for accuracy).
Hey presto! This got me past this error, and I just had to fix some arch related things and I was up and running again.
I guess if there isn't a Bitcode Enabled key/value defined, it defaults to YES.