[MacPorts] #58493: cctools: using clang < 5.0 as default assembler generates assembly errors in some cases

[MacPorts]

#58493: cctools: using clang < 5.0 as default assembler generates assembly errors
in some cases
----------------------+----------------------
  Reporter:  kencu    |      Owner:  jeremyhu
      Type:  defect   |     Status:  assigned
  Priority:  Normal   |  Milestone:
 Component:  ports    |    Version:
Resolution:           |   Keywords:
      Port:  cctools  |
----------------------+----------------------

Comment (by cjones051073):

 The more I think about the more I feel decoupling the macports clang
 version(s) that as uses internally from the llvm version that is used to
 build the cctools port is the way to go. There really is no technical
 reason these have to be the same. Then, as I describe above, instead of a
 single version, pass in a list of alternatives, in order of preference,
 and use the first that is found installed.

-- 
Ticket URL: <https://trac.macports.org/ticket/58493#comment:10>
MacPorts <https://www.macports.org/>
Ports system for macOS