[MacPorts] #53018: mercurial @4.0.1: error: $MACOSX_DEPLOYMENT_TARGET mismatch: now "10.9" but "10.11" during configure

[MacPorts]

#53018: mercurial @4.0.1: error: $MACOSX_DEPLOYMENT_TARGET mismatch: now "10.9" but
"10.11" during configure
------------------------+------------------------
  Reporter:  yabba      |      Owner:  seanfarley
      Type:  defect     |     Status:  assigned
  Priority:  Normal     |  Milestone:
 Component:  ports      |    Version:  2.3.5
Resolution:             |   Keywords:
      Port:  mercurial  |
------------------------+------------------------

Comment (by raimue):

 Replying to [comment:3 yabba]:
 > Give me the answer for: What _is_ the _usual_ setup?  ;)
 > Specify what you expect, please. :)
 >
 > I expected that the update continues to work like the years before. It
 stopped working that day, that's the reason I filed the bug.

 If we cannot reproduce the problem, we need your input what would be
 different on your system that is causing the problem. For example, did you
 ever make any changes to your macports.conf? Setting
 `macosx_deployment_target` in macports.conf would be something that could
 cause this.

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Ticket URL: <https://trac.macports.org/ticket/53018#comment:4>
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