[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 joostdekeijzer):

 Looking at what ports do for eg. selecting the correct MySQL/MariaDB
 version or the correct Python version, one way or the other in the port
 file "settings" are made.

 Example FontForge portfile setting pkg_config_path for Python version:\\
 https://github.com/macports/macports-
 ports/blob/master/graphics/fontforge/Portfile#L118

 Example Gimp3-devel for python pkgconfig path:\\
 https://github.com/macports/macports-
 ports/blob/master/graphics/gimp3-devel/Portfile#L179

 Example postfix portfile setting mariadb version paths:\\
 https://github.com/macports/macports-
 ports/blob/master/mail/postfix/Portfile#L214

 Example cmake portfile using variables in another way:\\
 https://github.com/macports/macports-
 ports/blob/master/devel/cmake/Portfile#L298 and line 309

 I guess there are many ways of doing this...

 We could leave the ImageMagick-6 paths "as is", only requiring ports that
 move to v7 to make the additional changes. I currently have the original
 ImageMagcik (v6) port installed plus my ImageMagick-7 port without
 problems.

 Otherwise maybe use port_select? But I'm not familiar with this.

-- 
Ticket URL: <https://trac.macports.org/ticket/51310#comment:35>
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