[MacPorts] #57198: libgcc8: build fails when libunwind-headers is installed

[MacPorts]

#57198: libgcc8: build fails when libunwind-headers is installed
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  Reporter:  miken32  |      Owner:  (none)
      Type:  defect   |     Status:  new
  Priority:  Normal   |  Milestone:
 Component:  ports    |    Version:  2.5.3
Resolution:           |   Keywords:
      Port:  libgcc8  |
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Comment (by ryandesign):

 Replying to [comment:15 Jahrme]:
 > Is there any direction for resolving the issue here?

 You've described the current situation and the available workarounds.

 > I do not know the proper resolution; perhaps there needs to be a
 mechanism that allows for the deactivation of a port during install.

 We have such a mechanism. It's called the
 "[wiki:PortfileRecipes#deactivatehack deactivate hack]". But we don't use
 it in scenarios like this one, because...

 > This would require checks that the port being deactivated is not
 currently "in use".

 ...MacPorts has no way of knowing whether a user is using the files
 installed by a port. Instead, in situations like this, we use the
 conflicts_build portgroup, which is what prints the message you showed
 above which told you what port you need to deactivate to proceed. By
 asking the user to do this, this ensures the user understands that that
 port will be deactivated and that its files will be unavailable.

-- 
Ticket URL: <https://trac.macports.org/ticket/57198#comment:18>
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