[MacPorts] #51310: ImageMagick: update to 7.x

[MacPorts]

#51310: ImageMagick: update to 7.x
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  Reporter:  mopihopi     |      Owner:  ryandesign
      Type:  update       |     Status:  assigned
  Priority:  Normal       |  Milestone:
 Component:  ports        |    Version:
Resolution:               |   Keywords:
      Port:  ImageMagick  |
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Comment (by ryandesign):

 I haven't looked at what you did in your branch.

 Yes, separate ImageMagick 6 and 7 ports that don't conflict is probably
 what we want.

 Is requiring all consumers of ImageMagick to specify PKG_CONFIG_PATH the
 only workable option? It's pretty inconvenient. Is that what other
 distributions are doing?

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Ticket URL: <https://trac.macports.org/ticket/51310#comment:34>
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