[MacPorts] #55068: gcc5 @5.4.0_2 update to 5.5.0

[MacPorts]

#55068: gcc5 @5.4.0_2 update to 5.5.0
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 Reporter:  nortcele  |      Owner:
     Type:  update    |     Status:  new
 Priority:  Normal    |  Milestone:
Component:  ports     |    Version:
 Keywords:            |       Port:  gcc5
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 Could gcc5 be updated to 5.5.0.

 Attached is a patch for the update.

 The file ```gcc5.5.0.diff``` to update the Porfile.

 Patch files ```files/macosx-version-min.patch``` and ```files/patch-gcc-
 system-h-map.diff``` are no longer needed.

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Ticket URL: <https://trac.macports.org/ticket/55068>
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