[MacPorts] #55630: port:clang-5.0 : ClangTargets-${cmake.build_type}.cmake refers to clang-5.0

[MacPorts]

#55630: port:clang-5.0 : ClangTargets-${cmake.build_type}.cmake refers to clang-5.0
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  Reporter:  RJVB       |      Owner:
      Type:  defect     |     Status:  new
  Priority:  Normal     |  Milestone:
 Component:  ports      |    Version:
Resolution:             |   Keywords:
      Port:  clang-5.0  |
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Comment (by RJVB):

 Patch attached. I think the "clang" target is new in 4.0(.1) (and
 apparently I fixed it in my own build without creating a patch).

 NB, clang takes way too long to build so I have NOT tested these mods
 after adapting them for use without `cmake.build_type`.

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Ticket URL: <https://trac.macports.org/ticket/55630#comment:3>
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