[MacPorts] #59056: waf portgroup: Allow location of waf executable to be configured

[MacPorts]

#59056: waf portgroup: Allow location of waf executable to be configured
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 Reporter:  ryandesign   |      Owner:  (none)
     Type:  enhancement  |     Status:  new
 Priority:  Normal       |  Milestone:
Component:  ports        |    Version:
 Keywords:               |       Port:
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 The waf portgroup currently assumes that the waf executable is located
 directly in `worksrcpath`.

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Ticket URL: <https://trac.macports.org/ticket/59056>
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