[MacPorts] #44129: cmake: fix build against libc++ on Lion

[MacPorts]

#44129: cmake: fix build against libc++ on Lion
----------------------+-------------------------
  Reporter:  mojca@…  |      Owner:  michaelld@…
      Type:  defect   |     Status:  new
  Priority:  Normal   |  Milestone:
 Component:  ports    |    Version:
Resolution:           |   Keywords:  lion
      Port:  cmake    |
----------------------+-------------------------

Comment (by mojca@…):

 You need to install MacPorts from scratch into a different prefix (also
 changing `applications_dir` etc.) and set `libc++` as default stdlib.

 These are my changes in `macports.conf`:
 {{{
 cxx_stdlib libc++
 delete_la_files yes
 buildfromsource always
 }}}
 If this is not documented anywhere on the wiki yet, it probably should be.

 You would then want to remove `configure.cxx_stdlib libstdc++` from the
 Portfile, but if you are on ML, it shouldn't have any effect anyway.

 See r110452, r131111, r131116.

 Running "`sudo port install cmake`" would trigger the error on Lion, but
 running "`sudo port install cmake configure.compiler=macports-clang-3.4`"
 works. I would imagine that running
     sudo port install cmake configure.compiler=macports-clang-3.3
 should reproduce the error on Mountain Lion. And I would imagine that ML
 with an old Xcode would fail in the same way as Lion does. I didn't test
 on anything below Lion yet.


 The problem seems to be caused by a *combination* of `libc++` and clang <
 3.4. (Maybe much older clang still works. And maybe it's different with
 different versions of `libc++`.)

-- 
Ticket URL: <https://trac.macports.org/ticket/44129#comment:13>
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