[MacPorts] #61864: ld64: add llvm10 and llvm11 variants

[MacPorts]

#61864: ld64: add llvm10 and llvm11 variants
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 Reporter:  ryandesign   |      Owner:  jeremyhu
     Type:  enhancement  |     Status:  assigned
 Priority:  Normal       |  Milestone:
Component:  ports        |    Version:
 Keywords:               |       Port:  ld64
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Ticket URL: <https://trac.macports.org/ticket/61864>
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