[MacPorts] #55444: clang-3.8 and later: All compilers are either blacklisted or unavailable

[MacPorts]

#55444: clang-3.8 and later: All compilers are either blacklisted or unavailable
-------------------------------------+-------------------------------------
  Reporter:  ryandesign              |      Owner:  jeremyhu
      Type:  defect                  |     Status:  new
  Priority:  Normal                  |  Milestone:
 Component:  ports                   |    Version:
Resolution:                          |   Keywords:  leopard snowleopard
      Port:  clang-3.8 clang-3.9     |  lion mountainlion
  clang-4.0 clang-5.0 clang-devel    |
-------------------------------------+-------------------------------------

Comment (by jeremyhu):

 macports-clang-3.7 is in the fallback list in base but only if the stdlib
 is libc++ (since the port itself requires C++11 and libc++):

 {{{
     if {${configure.cxx_stdlib} eq "libc++"} {
         # clang-3.5+ require libc++
         lappend compilers macports-clang-5.0 macports-clang-4.0

         if {${os.major} < 17} {
             # The High Sierra SDK requires a toolchain that can apply
 nullability to uuid_t
             lappend compilers macports-clang-3.9
         }

         if {${os.major} < 16} {
             # The Sierra SDK requires a toolchain that supports class
 properties
             lappend compilers macports-clang-3.7
         }
     }
 }}}

 I suppose we could make that check based on `[file exists
 /usr/lib/libc++.dylib] || ${configure.cxx_stdlib} eq "libc++"` since the
 port itself forces the use of libc++ even when it's not default (Lion /
 ML).

 Thoughts?

--
Ticket URL: <https://trac.macports.org/ticket/55444#comment:1>
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