[MacPorts] #46833: glpng fails to build due to macro conflict with libpng

[MacPorts]

#46833: glpng fails to build due to macro conflict with libpng
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  Reporter:  jeremyhu  |      Owner:  ryandesign
      Type:  defect    |     Status:  new
  Priority:  Normal    |  Milestone:
 Component:  ports     |    Version:
Resolution:            |   Keywords:
      Port:  glpng     |
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Changes (by ryandesign):

 * cc: smcguffee (added)


Comment:

 Has duplicate #55855.

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Ticket URL: <https://trac.macports.org/ticket/46833#comment:2>
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