[MacPorts] #58260: libgcc8 build fails due to "Atomic" error on Mojave

[MacPorts]

#58260: libgcc8 build fails due to "Atomic" error on Mojave
---------------------------+--------------------
  Reporter:  physicsbeany  |      Owner:  (none)
      Type:  defect        |     Status:  new
  Priority:  Normal        |  Milestone:
 Component:  ports         |    Version:  2.5.4
Resolution:                |   Keywords:  atomic
      Port:  libgcc8       |
---------------------------+--------------------
Description changed by physicsbeany:

Old description:

> Recently upgraded to MacOS Mojave from High Sierra, and followed general
> Macports instructions for migrating my old ports. Things went fine until
> libgcc8 (needed to do my py27-scipy installation). Initially, this failed
> because of Unwind issues. I solved this by following the advice in ticket
> #57198.
>
> Now, however, the compilation fails because of an "Atomic" error.
> Specifically, the first instance of the Error in the log file is:
>

> {{{
> :info:build
> /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/ucred.h:94:2:
> error: '_Atomic' does not name a type
> :info:build   _Atomic u_long          cr_ref;  /* reference count */
> }}}
>
> Full logfile attached
>
> Some Googling indicates that this may be avoided by defining
> __STDC_NO_ATOMICS__, but I'm not certain this is the right answer (and I
> don't know how to do this as part of a Macports installation).

New description:

 Recently upgraded to MacOS Mojave from High Sierra, and followed general
 Macports instructions for migrating my old ports. Things went fine until
 libgcc8 (needed to do my py27-scipy installation). Initially, this failed
 because of Unwind issues. I solved this by following the advice in ticket
 #57198.

 Now, however, the compilation fails because of an "Atomic" error.
 Specifically, the first instance of the Error in the log file is:


 {{{
 :info:build
 /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/sys/ucred.h:94:2:
 error: '_Atomic' does not name a type
 :info:build   _Atomic u_long          cr_ref;  /* reference count */
 }}}

 The full logfile is 64 MB; I've uploaded the last 50K lines of it.

 Some Googling indicates that this may be avoided by defining
 __STDC_NO_ATOMICS__, but I'm not certain this is the right answer (and I
 don't know how to do this as part of a Macports installation).

--

-- 
Ticket URL: <https://trac.macports.org/ticket/58260#comment:1>
MacPorts <https://www.macports.org/>
Ports system for macOS