Use predefined $(RM) in clean rule, and -r only for (expected) directories
Use predefined $(RM) in clean rule, and -r only for (expected) directories


git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@203271 91177308-0d34-0410-b5e6-96231b3b80d8

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