[MacPorts] #63748: xsel 1.2.0 fails to build on macOS 12.0.1

[MacPorts]

#63748: xsel 1.2.0 fails to build on macOS 12.0.1
---------------------------+------------------------
  Reporter:  derekschrock  |      Owner:  ryandesign
      Type:  defect        |     Status:  assigned
  Priority:  Normal        |  Milestone:
 Component:  ports         |    Version:  2.7.1
Resolution:                |   Keywords:  monterey
      Port:  xsel          |
---------------------------+------------------------

Comment (by ryandesign):

 Use `eq` instead of `==` when performing string comparisons in Tcl. And
 it's a good idea to add a comment in the Portfile, above your change, with
 a link to the upstream bug report that explains why it's there.

 As for whether this fix is correct, as I've said, I have no information
 and take no responsibility for it. If this breaks something, I hope that
 you will follow up with any necessary fixes; I don't want to be involved.

-- 
Ticket URL: <https://trac.macports.org/ticket/63748#comment:11>
MacPorts <https://www.macports.org/>
Ports system for macOS