[MacPorts] #56373: fix lack of optimization in compiling pymol on clang compilers

[MacPorts]

#56373: fix lack of optimization in compiling pymol on clang compilers
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  Reporter:  jwhowarth  |      Owner:  (none)
      Type:  update     |     Status:  new
  Priority:  Normal     |  Milestone:
 Component:  ports      |    Version:
Resolution:             |   Keywords:  science
      Port:  pymol      |
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Comment (by jwhowarth):

 The origin of the usage of -fno-strict-aliasing in python-2.7's
 /opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/_sysconfigdata.py,
 is described in this web page

 [https://wiki.gentoo.org/wiki/Project:Python/Strict_aliasing]

 However, this differs from the reason we are using it now in pymol which
 is due to a clang bug causing one of the source files to crash the
 compiler when -fstricti-aliasing. In general, one would like to avoid
 -fno-strict-aliasing as it can limit optimization options for the
 compiler. However considering that the alternative is to compile with no
 optimization at all, it is a reasonable trade-off here.

 A reasonable explanation of strict aliasing can be found at
 [https://cellperformance.beyond3d.com/articles/2006/06/understanding-
 strict-aliasing.html]

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Ticket URL: <https://trac.macports.org/ticket/56373#comment:7>
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