[Analyzer] Fetch :podspec dependencies when the spec is missing

[Outdated] Friendly error when no podspec present for external source deps

Make de-integration wording less verbose.

This reverts commit bf6fad15.

Fix lint in Xcode 7.2, it requires `-destination`

While `watchos` and `tvos` are fairly straightforward, I chose iPhone 4s
as destination for `ios` since it is seems like the most likely to
work with any version of Xcode at this point.

[Project] Change config defines to be prefixed