Makefile.rules: Pass SWIFTFLAGS to link commands too
Makefile.rules: Pass SWIFTFLAGS to link commands too

Link commands need to be given the right triple for cross-compilation,
let's just pass the full set of SWIFTFLAGS to them.

apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb