[MacPorts] #74310: pre-configure and post-configure phases should set SDKROOT environment variable

[MacPorts]

#74310: pre-configure and post-configure phases should set SDKROOT environment
variable
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  Reporter:  breun   |      Owner:  jmroot
      Type:  defect  |     Status:  assigned
  Priority:  Normal  |  Milestone:
 Component:  base    |    Version:
Resolution:          |   Keywords:
      Port:          |
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Comment (by jmroot):

 Environment variables are not associated with phases or targets, but
 rather with commands (a target can run multiple commands). I'm not fond of
 the special casing of `DEVELOPER_DIR`, especially since it makes it
 difficult to get rid of it if you need it to not be set.

 Perhaps there is a class of environment variables that we do want to set
 all the time, but first we have to define what "all the time" means here:
 Even if you're only running Tcl commands? Just for `system`? For `exec` as
 well? Or some other definition?

 Once that is answered, a general mechanism could be added, and
 (importantly) a way to turn it off.

-- 
Ticket URL: <https://trac.macports.org/ticket/74310#comment:2>
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