[MacPorts] #53931: clang's ld doesn't recognise "-lto_library" flag on 10.6

[MacPorts]

#53931: clang's ld doesn't recognise "-lto_library" flag on 10.6
-------------------------------------------------+-------------------------
  Reporter:  mojca                               |      Owner:  jeremyhu
      Type:  defect                              |     Status:  new
  Priority:  Normal                              |  Milestone:
 Component:  ports                               |    Version:
Resolution:                                      |   Keywords:  snowleopard
      Port:  clang-3.9 clang-4.0 llvm-3.9        |
  llvm-4.0                                       |
-------------------------------------------------+-------------------------

Comment (by kencu):

 This commit <https://reviews.llvm.org/D25932> would appear to explain why
 LTO is now automatically invoked on newer llvm versions, I think. It would
 appear to have become the default to invoke LTO when this commit was
 included in an llvm version release -- presumably after 3.9.0 and before
 3.9.1 as yours invokes it automatically whereas mine does not.

 So I guess the remaining question is why ld64 finds the LTO library
 without apparent troubles on my machine, but not on your machine...

--
Ticket URL: <https://trac.macports.org/ticket/53931#comment:7>
MacPorts <https://www.macports.org/>
Ports system for macOS