[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):

 Replying to [comment:4 RJVB]:
 > Replying to [comment:2 jeremyhu]:
 > > For the assembler issue, the problem is that MacPorts doesn't allow us
 to solve it easily.
 >
 > What issue?

 depends_run are treated as build dependencies.  Base does not allow a way
 to specify depends_run as a post-install/post-activate dependency.

 > The fact that invoking cctool's `as` with the `-q` option doesn't give
 control over which clang it will use?

 I proposed a simple solution to that.

 > I'm not sure if that's an actual issue. Calling `as -q` means you're
 using the command as a proxy so the actual work is done by an application
 that isn't part of the port.

 Yes.

 > I cannot remember if I ever checked this but I wouldn't be surprised if
 `as -q` invokes the system clang.

 It invokes ${prefix}/clang.  See:

 {{{
 $ as -q
 as: assembler (/opt/local/bin/clang) not installed
 }}}

 > That would be in line with what $prefix/bin/gmake does: it too will
 invoke executables from the system toolchain unless told otherwise.

 gmake doesn't have any logic in that regard.  It sets up CC et al per spec
 and POSIX dictates how they are found via PATH.

 > Control over the clang version could be nice but that's something that
 shouldn't have to be gcc's concern instead of cctools'.

 And that's exactly my point.  cctools cannot depend on the clang ports and
 thus cannot specify what version of clang is used because MacPorts does
 not support the type of dependency needed here.

--
Ticket URL: <https://trac.macports.org/ticket/54773#comment:6>
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