[MacPorts] #58199: cmake: build failure on OSX 10.11 due to LegacySupport PortGroup

[MacPorts]

#58199: cmake: build failure on OSX 10.11 due to LegacySupport PortGroup
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  Reporter:  dbl001  |      Owner:  michaelld
      Type:  defect  |     Status:  assigned
  Priority:  Normal  |  Milestone:
 Component:  ports   |    Version:  2.5.4
Resolution:          |   Keywords:
      Port:  cmake   |
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Comment (by michaelld):

 According to < https://trac.macports.org/wiki/XcodeVersionInfo >, 10.11
 can use any Xcode 7.2.1 or 7.3.1 -- which I'm guessing do not correctly
 define `clock_gettime` (etc) -- or Xcode 8.0.0 to 8.2.1 -- which I'm
 guessing do include those routines. My install has 8.2.1, as do I think
 all of the folks here having the issue ... hence I can't actually test
 whether Xcode 8.0.0 provides this feature or not; just a guess.

 Chris: Could you make a copy of your VM & update the Xcode to 8.0.0 & see
 if the SDK provides `clock_gettime` in the `time.h` header? That would
 probably be the fastest way to confirm. Then you can delete your new VM or
 not as you see fit.

-- 
Ticket URL: <https://trac.macports.org/ticket/58199#comment:29>
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