[MacPorts] #54773: port:libgcc/port:gcc7: proposed modifications, efficiency + libc++ support

[MacPorts]

#54773: port:libgcc/port:gcc7: proposed modifications, efficiency + libc++ support
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  Reporter:  RJVB         |      Owner:
      Type:  enhancement  |     Status:  new
  Priority:  Normal       |  Milestone:
 Component:  ports        |    Version:
Resolution:               |   Keywords:  haspatch
      Port:  gcc7 libgcc  |
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Comment (by jeremyhu):

 I'm not a fan of the +with_libgcc bits:

   1. I'd rather someone that can read GPL3 figure out how to modify the
 build system to avoid the duplicated building.
   2. The dylib ids are incorrect.  It looks like you leave them with the
 versioned path which defeats one of the main points of the libgcc port.
 You should still have the actual files installed into libgcc with
 appropriate dylib ids and have gcc7 symlink those.

 For the +libcxx changes... is g++ expected to be compatible with libc++?
 I'd rather not do something like that unless FSF or llvm sign up for that
 level of support.

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Ticket URL: <https://trac.macports.org/ticket/54773#comment:1>
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