[MacPorts] #62708: tmux crashes when building with macOS SDK 11.0 on macOS 10.15

[MacPorts]

#62708: tmux crashes when building with macOS SDK 11.0 on macOS 10.15
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  Reporter:  tgyurci  |      Owner:  tessus
      Type:  defect   |     Status:  assigned
  Priority:  Normal   |  Milestone:
 Component:  ports    |    Version:
Resolution:           |   Keywords:
      Port:  tmux     |
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Comment (by kencu):

 open source software does not always do a robust check for functions it
 uses. Often the best you can expect is a test that the function definition
 exists in the headers.

 When using a newer SDK to build software on or for an older system than
 the SDK, it is common to have the function found in the sdk but not
 available on the target system.

 MacPorts tries to use the sdk that matches the system to minimize this.
 And we have a process to add symbols to older systems that is also handy.
 So that is the official intention, to date.

 If you have software skills and a better, more robust idea, please join us
 in making this better for everyone!

-- 
Ticket URL: <https://trac.macports.org/ticket/62708#comment:6>
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