Defaulting to iOS 3.0 when LLVM has to guess the version is no longer a useful
option and can give surprising results (like tail calls being disabled).
5.0 seems like a reasonable compromise as a platform that's still interesting
to some people.
rdar://problem/15567348
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196912 91177308-0d34-0410-b5e6-96231b3b80d8