[MacPorts] #60244: xmgrace build fails: Requested variants "+perl5_28" do not match those the build was started with: "+perl5_26"

[MacPorts]

#60244: xmgrace build fails: Requested variants "+perl5_28" do not match those the
build was started with: "+perl5_26"
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 Reporter:  barbarabrena          |      Owner:  (none)
     Type:  defect                |     Status:  new
 Priority:  Normal                |  Milestone:
Component:  ports                 |    Version:
 Keywords:  catalina "+perl5_28"  |       Port:  grace, gnuplot, motif
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 I work with MacOs Catalina 10:15:1 and I have installed the related
 macports. When I try to install xmgrace or motifs, or gnuplot, I get the
 message:
 Error: Requested variants "+perl5_28" do not match those the build was
 started with: "+perl5_26".
 Error: Please use the same variants again, or run 'port clean ossp-uuid'
 first to remove the existing partially completed build.

 I have no idea how to solve this. It worked smoothly in the previous OS,
 like Sierra and high sierra.

 In addition the recommended 'port clean ossp-uuid' does not work for me.
 An I do not know how to modify which variants I am requested.
 Thank you a lot for your help, I am totally stuck with this.

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Ticket URL: <https://trac.macports.org/ticket/60244>
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