[MacPorts] #56737: graphene 1.8.2: difficulty building +universal

[MacPorts]

#56737: graphene 1.8.2: difficulty building +universal
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  Reporter:  kencu     |      Owner:  dbevans
      Type:  defect    |     Status:  assigned
  Priority:  Normal    |  Milestone:
 Component:  ports     |    Version:  2.5.2
Resolution:            |   Keywords:
      Port:  graphene  |
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Changes (by Ionic):

 * cc: Ionic (added)


Comment:

 The mentioned PR just enables SSE2 checking globally. Yes, that probably
 fixes the issue for `x86_64` and `x86` universal builds, because it will
 be enabled for both arches (since we don't have x86-family CPUs that are
 old enough to not support SSE2), but... will likewise fail on universal
 builds mixing `x86` or `x86_64` and `ppc`, since the latter does not know
 or implement SSE.

 The authors
 [https://github.com/ebassi/graphene/commit/7e3f7358a1fff34b93325081313eca3bb762a29f
 #diff-67e997bcfdac55191033d57a16d1408aR120 required at least GCC 4.2 for
 SSE2 support on non-x86_64 platforms originally] and later
 [https://github.com/ebassi/graphene/commit/83ac0201c165e1314ffbb12cf9508d9497643122
 bumped up the requirement for SSE2 on x86 to GCC 4.9], with a reasoning
 that does sound a bit shady. I do not understand why they bumped up the
 requirement if it worked with GCC 4.2 (coincidentally one of the versions
 we particularly care about, since some older platforms do have GCC 4.2 as
 the system compiler), but maybe it did cause runtime problems I'm not
 aware of.

 Instead of a workaround like this, wouldn't it be better to fix the actual
 problem? For that matter, what IS the actual problem? Why does merging
 these files fail? Is there anything we can do about this and support
 universal builds that have diverging CPU features?

-- 
Ticket URL: <https://trac.macports.org/ticket/56737#comment:6>
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