[MacPorts] #48926: Xcode 7 update seems to cause /usr/bin/clang --version to hang which causes ./configure to hang

[MacPorts]

#48926: Xcode 7 update seems to cause /usr/bin/clang --version to hang which causes
./configure to hang
----------------------+--------------------------------
  Reporter:  david@…  |      Owner:  macports-tickets@…
      Type:  defect   |     Status:  new
  Priority:  Normal   |  Milestone:
 Component:  ports    |    Version:  2.3.3
Resolution:           |   Keywords:
      Port:           |
----------------------+--------------------------------

Comment (by ryandesign@…):

 Replying to [comment:4 david@…]:
 > Some builds hang + ps shows this...
 > {{{
 > imac# psall | grep -i make
 > macports        11474   0.0  0.0  2442588   1028 s002  S+   10:09AM
 0:00.00 sh -c
 /Applications/Xcode-6.4.app/Contents/Developer/usr/bin/xcodebuild -sdk ''
 -find make 2> /dev/null
 > macports        11472   0.0  0.0  2444092    684 s002  S+   10:09AM
 0:00.00 make -v
 > macports        11471   0.0  0.0  2443612   1048 s002  S+   10:09AM
 0:00.00 sh -c "make" -v 2>&1
 > macports        11382   0.0  0.0  2471900  14436 s002  S+   10:09AM
 0:00.15 /opt/local/bin/perl5.20 Makefile.PL INSTALLDIRS=vendor
 CC=/usr/bin/clang LD=/usr/bin/clang
 > macports        11381   0.0  0.0  2435420   1060 s002  S+   10:09AM
 0:00.03 sh -c  cd
 "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_perl_p5
 -net-ssleay/p5.20-net-ssleay/work/Net-SSLeay-1.71" &&
 /opt/local/bin/perl5.20 Makefile.PL INSTALLDIRS=vendor CC="/usr/bin/clang"
 LD="/usr/bin/clang"
 > root            11955   0.0  0.0  2423552     24 s000  R+   10:11AM
 0:00.00 grep -i make
 > macports        11475   0.0  0.1  2593712  27568 s002  S+   10:09AM
 0:00.18 /Applications/Xcode-6.4.app/Contents/Developer/usr/bin/xcodebuild
 -sdk  -find make
 > }}}
 > Notice -sdk being passed with an empty sdk.

 Maybe that's a bug in that particular port? Or maybe you need to rebuild
 the corresponding perl port (in this case, perl5.20) so that it
 understands you want to use a different Xcode location now? I know that
 some software, including perl, remembers such details about your build
 system, and tries to use those remembered details later—in the case of
 perl: when building modules.

 > I've looked through the Macports developer guide + there appears to be
 now way to set the -sdk version to use.

 The sdk is influenced by the macports.conf variable `macosx_sdk_version`.
 So you can set, for example, "`macosx_sdk_version 10.11`" if you want to
 use the MacOSX10.11 sdk. This option is undocumented because we do not
 support users changing it. That means that for any particular port it
 might work, or it might have no effect. Or, in the case of perl, it might
 use a previously-remembered value. Also, if you change the sdk, you must
 set "`buildfromsource always`", otherwise you might get binaries from our
 build server that were not built with your sdk choice.

-- 
Ticket URL: <https://trac.macports.org/ticket/48926#comment:6>
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