[MacPorts] #58260: gcc{6, 7, 8, 9} : Build failures due to "Atomic" error with macOS 10.4.4 and Xcode 10.2

[MacPorts]

#58260: gcc{6,7,8,9} : Build failures due to "Atomic" error with macOS 10.4.4 and
Xcode 10.2
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  Reporter:  physicsbeany                        |      Owner:  (none)
      Type:  defect                              |     Status:  new
  Priority:  Normal                              |  Milestone:
 Component:  ports                               |    Version:  2.5.4
Resolution:                                      |   Keywords:  mojave
      Port:  gcc9 gcc8 gcc7 gcc6 libgcc-devel    |
  libgcc8 libgcc7 libgcc6                        |
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Comment (by n7zzt):

 ok, so it appears that I am not the only one to notice. Also, instead of
 migrating my old ports from High Sierra, I simply made a list of those
 items Needed and installed new. However, because of this "Atomic Error",
 gcc9 fails to build.

 I have also noted that there seems to be an increasing frequency of
 breakages of this type across more and more packages as time goes on. Is
 this a deep error inside the compiler somewhere?

 Last item (not directly related to this ticket, but relevant): this site
 needs to be properly audited for accessibility. Filing the ticket was a
 real exercise in frustration as not all form controls were immediately
 accessible and catalogued by my screen reader. If this doesn't tell you,
 then perhaps I need to make it plainly clear: I am totally blind and
 website ease of use for me is a BIG priority. Right now, trying to
 navigate through this site is a bit of a PITA. I had to reload it before
 the screen reader would catalogue all the controls, links, edit boxes,
 checkboxes and the like. Even then, This particular edit box was not
 visible until I dug deep into this table entry to find it. This is
 something the web development team needs to take a look at. If they have
 questions, I can be reached via return email.

 very last item, exactly what causes an "Atomic Error" anyway? trying to
 dig around on google only confused things.

-- 
Ticket URL: <https://trac.macports.org/ticket/58260#comment:19>
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