[build] Add swift-autolink-extract to macOS toolchains
[build] Add swift-autolink-extract to macOS toolchains

Including this symlink makes it easier to cross compile for Linux which
requires use of this tool.

glessard/swift,glessard/swift,apple/swift,roambotics/swift,apple/swift,apple/swift,roambotics/swift,benlangmuir/swift,apple/swift,apple/swift,glessard/swift,glessard/swift,benlangmuir/swift,glessard/swift,glessard/swift,roambotics/swift,benlangmuir/swift,roambotics/swift,benlangmuir/swift,apple/swift,benlangmuir/swift,benlangmuir/swift,roambotics/swift,roambotics/swift