[MacPorts] #55441: libcxx, libcxxabi: also install into the SDKs

[MacPorts]

#55441: libcxx, libcxxabi: also install into the SDKs
----------------------------------+-------------------------------
 Reporter:  ryandesign            |      Owner:  jeremyhu
     Type:  enhancement           |     Status:  new
 Priority:  Normal                |  Milestone:
Component:  ports                 |    Version:
 Keywords:  snowleopard haspatch  |       Port:  libcxx, libcxxabi
----------------------------------+-------------------------------
 On Snow Leopard, the libcxx port installs libc++ into /usr/lib. But if a
 program uses an SDK, it can fail somewhat mysteriously. From an attempt to
 install cmake with libc++ on 10.6:

 {{{
     /opt/local/bin/clang++-mp-3.7  -pipe -Os -stdlib=libc++ -arch x86_64
 -isysroot /Developer/SDKs/MacOSX10.6.sdk -mmacosx-version-min=10.6
 -Wl,-search_paths_first -Wl,-headerpad_max_install_names -L/opt/local/lib
 -Wl,-headerpad_max_install_names -arch x86_64
 CMakeFiles/cmTC_53c5f.dir/testCXXCompiler.cxx.o  -o cmTC_53c5f
     ld: library not found for -lc++
 }}}

 Because the cmake build uses `-isysroot /Developer/SDKs/MacOSX10.6.sdk`,
 it's looking for libc++ in /Developer/SDKs/MacOSX10.6.sdk/usr/lib and not
 finding it. Could we install it to there as well?

 Xcode 3 on Snow Leopard also installs the 10.5 SDK. I'm not sure if the
 port should try to install to there as well if present.

 Xcode 3 also optionally installs the 10.4u SDK. I assume it should not
 install to the 10.4u SDK since the port already does not work on Tiger.

 If libcxx is modified, I assume libcxxabi should be modified too.

--
Ticket URL: <https://trac.macports.org/ticket/55441>
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