[MacPorts] #62944: grpc: py-grpcio port build failures

[MacPorts]

#62944: grpc: py-grpcio port build failures
-----------------------------+--------------------
  Reporter:  mascguy         |      Owner:  (none)
      Type:  defect          |     Status:  new
  Priority:  Normal          |  Milestone:
 Component:  ports           |    Version:
Resolution:                  |   Keywords:
      Port:  grpc py-grpcio  |
-----------------------------+--------------------

Comment (by mascguy):

 I'm not sure this is related, but I'm also seeing odd failures for `py-
 pyarrow`:

 {{{
 Command failed: ninja all -j8 -v
 Exit code: 1
 Error: Failed to configure py37-pyarrow: command execution failed
 DEBUG: Error code: NONE
 DEBUG: Backtrace: command execution failed
     while executing
 "$post $targetname"
 Error: See /opt/local/var/macports/logs
 /_opt_bblocal_var_buildworker_ports_build_ports_devel_apache-
 arrow/py37-pyarrow/main.log for details.
 DEBUG: process_cmd failed: can't read "string": no such variable
     while executing
 "return $string"
     (procedure "wrapline" line 7)
     invoked from within
 "wrapline $line $maxlen $indent $indentline"
     (procedure "wrap" line 15)
     invoked from within
 "wrap "Follow https://guide.macports.org/#project.tickets if you believe
 there is a bug." -${len}"
     (procedure "print_tickets_url" line 4)
     invoked from within
 "print_tickets_url"
     ("uplevel" body line 82)
     invoked from within
 "uplevel 1 $block"
     (procedure "foreachport" line 20)
     invoked from within
 "foreachport $portlist {
         array unset portinfo
         # If we have a url, use that, since it's most specific
         # otherwise try to map the..."
     (procedure "action_target" line 10)
     invoked from within
 "$action_proc $action $portlist [array get global_options]"
     (procedure "process_cmd" line 110)
     invoked from within
 "process_cmd $remaining_args"
     ("uplevel" body line 3)
     invoked from within
 "uplevel 1 $body"
 Error: process_cmd failed: can't read "string": no such variable
 }}}

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Ticket URL: <https://trac.macports.org/ticket/62944#comment:3>
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