[MacPorts] #52172: fix for current Xcode 8 build of sbcl

[MacPorts]

#52172: fix for current Xcode 8 build of sbcl
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 Reporter:  howarth.at.macports@…  |      Owner:  macports-tickets@…
     Type:  defect                 |     Status:  new
 Priority:  Normal                 |  Milestone:
Component:  ports                  |    Version:  2.3.4
 Keywords:                         |       Port:  sbcl
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 The build of sbcl fails under the most recent Xcode 8 beta releases due to
 the removal of the libgcc_s.10.4.dylib stub from /usr/lib in the
 associated Command Line Tools. Assuming MacPorts only supports 10.4 and
 later at this point, the attached Portfile diff solves the problem by
 inserting "&& export SBCL_MACOSX_VERSION_MIN=10.5" into the environmental
 set by build phase script.

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Ticket URL: <https://trac.macports.org/ticket/52172>
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