[MacPorts] #63137: gromacs: Error: clang-5.0 is not supported on this macOS release (Darwin 20).

[MacPorts]

#63137: gromacs: Error: clang-5.0 is not supported on this macOS release (Darwin
20).
----------------------+----------------------
  Reporter:  rikta43  |      Owner:  dstrubbe
      Type:  defect   |     Status:  assigned
  Priority:  Normal   |  Milestone:
 Component:  ports    |    Version:  2.7.1
Resolution:           |   Keywords:  bigsur
      Port:  gromacs  |
----------------------+----------------------

Comment (by ryandesign):

 Looks like this happens because of these three lines:
 {{{
 # this line is needed to allow use of gcc
 configure.cxx_stdlib   libstdc++
 PortGroup           cxx11 1.1
 }}}

 Setting configure.cxx_stdlib to libstdc++ causes the cxx11 1.1 portgroup
 to select a compiler that is known to work on those old systems that
 defaulted to libstdc++ (OS X 10.8 and earlier), i.e. clang 5.0.

 [changeset:9ce0ca9fcd7042ae34525535da4175e7bd50bd6a/macports-ports The
 cxx11 1.1 portgroup is deprecated] since over a year; no port should be
 using it anymore. The line that includes this portgroup should be removed
 from the portfile and the required version of the C++ standard should
 instead be indicated by setting e.g. `configure.cxx_standard 2011`.

 Whether it remains necessary to switch the C++ standard library to
 libstdc++ I don't know. If this port continues to use G++ to compile C++
 code, it probably does. So long as this port does not use any C++
 libraries from other ports, and so long as no other ports use C++
 libraries of this port, that's probably fine.

-- 
Ticket URL: <https://trac.macports.org/ticket/63137#comment:2>
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