[MacPorts] #58779: base: ports cannot use SDK inside of Developer dir unless using Xcode build type

[MacPorts]

#58779: base: ports cannot use SDK inside of Developer dir unless using Xcode build
type
---------------------+-----------------------
  Reporter:  Ionic   |      Owner:  (none)
      Type:  defect  |     Status:  new
  Priority:  Normal  |  Milestone:
 Component:  base    |    Version:  2.5.99
Resolution:          |   Keywords:  tracemode
      Port:          |
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Comment (by Ionic):

 This behavior might be a peculiarity of qmake(5). qmake figures out the
 SDK directory itself, probably in a hardcoded fashion and does not use
 information provided by MacPorts to do this (other than selecting the SDK
 version).

 I've looked a bit further and noticed that
 `portconfigure::configure_get_sdkroot` returns an empty string if the SDK
 version passed in (which should be `configure.sdk_version`) matches the
 running macOS version and `/usr/include` exists, so getting the actual SDK
 location will turn out to be a bit difficult.

 [6b27854906b3c19d209c50ff59a4fa78d42f3a03/macports-base] only set
 `use_xcode` to `true` if CLTs are not installed, but that's not relevant
 in this case.


 Arguably, I guess we could tell qmake to use `/` as the SDK root if
 `configure.sdkroot` turns out to be empty... but do we really want this?

-- 
Ticket URL: <https://trac.macports.org/ticket/58779#comment:2>
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