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

[MacPorts]

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

Comment (by jeremyhu):

 > Making this an issue would basically mean that cmake, gmake and all
 ports shipping an IDE or software that can invoke a compiler would also
 have to provide variants that determines the default clang-mp

 Nope.  There's no reason for it to be done at that level.  I'm saying you
 could change gcc (just like you are proposing with your patch) to include
 the full path.  Eg:

 #define ASM_OPTIONS "-q --clang=/opt/local/bin/clang-mp-5.0"

 Then anyone using gcc would spawn 'as -q --clang=/opt/local/bin/clang-
 mp-5.0"

 Alternatively, create a separate port that provides /opt/local/bin/clang-
 as and have that port depend on both cctools and a specific version of
 clang such that it just does:

     #!/bin/sh
     exec @@PREFIX@@/bin/as -q --clang=@@PREFIX@@/bin/clang-
 mp-@@CLANG_VERSION@@ "${@}"

 Or we can breakup the cctools port into separate ports such that
 install_name_tool and as are provided by separate ports, allowing the llvm
 ports to depend on install_name_tool and the as port to depend on clang.

--
Ticket URL: <https://trac.macports.org/ticket/54773#comment:10>
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