I have a project which links with 3rd party SDKs (AdMob and others). With Xcode 8.3.1, I get the following linker warnings when building the archive that gets uploaded to iTunes Connect (Xcode: Product -> Archive):
ld: warning: Linker asked to preserve internal global: '__block_descriptor_tmp'
ld: warning: Linker asked to preserve internal global: '__block_literal_global'
The last time I updated the app, I was using an older version of Xcode and didn't see any linker warnings.
Is this warning due to the 3rd party SDKs having been built with an older version of Xcode?
Is it something to worry about?