[MacPorts] #66549: qt511-qtimageformats @5.11.3_2: Could not resolve SDK Path for 'macosx10.11' using --show-sdk-path

[MacPorts]

#66549: qt511-qtimageformats @5.11.3_2: Could not resolve SDK Path for
'macosx10.11' using --show-sdk-path
-----------------------------------+---------------------------------
  Reporter:  thetrial              |      Owner:  MarcusCalhoun-Lopez
      Type:  defect                |     Status:  assigned
  Priority:  Normal                |  Milestone:
 Component:  ports                 |    Version:  2.8.0
Resolution:                        |   Keywords:  elcapitan legacy-os
      Port:  qt511-qtimageformats  |
-----------------------------------+---------------------------------

Comment (by jmroot):

 The silly thing about all this is that you don't even need to use an SDK
 on < 10.14; all the headers and libs are present under `/` (i.e.
 `/usr/include` for headers) if you have the CLTs installed. I think that's
 the logic behind Apple not including a 10.11 SDK with Xcode 8 or the CLTs.

 Downloading Xcode 7.3.1 and copying the 10.11 SDK out of the app bundle
 and into `/Library/Developer/CommandLineTools/SDKs` does seem to work, at
 least for the purposes of `env
 DEVELOPER_DIR=/Library/Developer/CommandLineTools xcrun --sdk macosx10.11
 --show-sdk-path`. However it seems like it would be preferable to patch
 whatever needs to be patched to convince the build system that the SDK
 flags can simply be omitted on these older OS versions.

-- 
Ticket URL: <https://trac.macports.org/ticket/66549#comment:18>
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