[lldbsuite] Fix the mac version decorator to work on non-mac platforms
[lldbsuite] Fix the mac version decorator to work on non-mac platforms

Summary: On non-mac platforms, mac_ver returns an empty string which when converted to LooseVersion has no "version" property. This causes a failure when the decorator executes. Instead, check whether the value returned from mac_ver is an empty string and avoid the LooseVersion comparison.

Reviewers: labath, davide, asmith, shafik, jingham

Reviewed By: jingham

Subscribers: jingham, lldb-commits

Differential Revision: https://reviews.llvm.org/D53208

git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@344623 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb,llvm-mirror/lldb,llvm-mirror/lldb,apple/swift-lldb,llvm-mirror/lldb,apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb,apple/swift-lldb