[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:  High     |  Milestone:
Component:  ports    |    Version:  2.3.3
 Keywords:           |       Port:
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 Unfortunately I just upgraded to Xcode 7 on Yosemite.

 It appears Apple has introduce an ugly bug where the update to Xcode 7
 removes Xcode 6.x which also removes the macos10.10 SDK.

 Besides the already reported problems, like wireshark build break, another
 more ugly oddity has surfaced.

 Many builds hang in the configuration step, running ./configure.

 I've attached a log file from ffmpeg with 'set +x' added to top of
 ./configure which illustrates the problem.

 Inside the ./configure probe_cc() function around line 3555 I added...

 {{{
     # DRF
     echo "DRF: probe_cc(): cc=$_cc"
     echo "DRF: probe_cc(): before: clang version"
     $_cc --version 2>&1
     echo "DRF: probe_cc(): after: clang version"
 }}}

 I've attached the log file which shows clang hanging.

 This makes no sense to me, as running /usr/bin/clang --version on the
 command line works.

 Also changing --version to --help or --foo produce the same hang.

 If I hack _cc to be /opt/local/bin/clang then the command works, so I
 suspect something's amiss in the Xcode update.

 My question is... If anyone knows a work around to fix this, please update
 this ticket.

 I've opened a bug with Apple asking how to reinstall Xcode 6.x in parallel
 with Xcode 7 + will update this ticket if they respond with any useful
 information.

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