[MacPorts] #57412: clang ports: add runtime dependency on cctools

[MacPorts]

#57412: clang ports: add runtime dependency on cctools
-------------------------------------------------+-------------------------
  Reporter:  ryandesign                          |      Owner:  (none)
      Type:  defect                              |     Status:  new
  Priority:  Normal                              |  Milestone:
 Component:  ports                               |    Version:
Resolution:                                      |   Keywords:
      Port:  clang-5.0, clang-6.0, clang-7.0,    |
  clang-devel                                    |
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Comment (by ryandesign):

 Ok. I was worried for a minute about the fact that cctools has llvm
 variants, but that's just llvm, not clang, and only clang needs the
 cctools dependency, so we should be fine.

 clang-3.9 and later already include the following block:

 {{{
 if {[string match macports-clang-* ${configure.compiler}]} {
     depends_build-append port:cctools
     depends_skip_archcheck-append cctools
 }
 }}}

 I guess we should change that to `depends_lib` and revbump.

-- 
Ticket URL: <https://trac.macports.org/ticket/57412#comment:8>
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