Build failure on macOS 10.10–10.11: `cubeb_audio_dump.cpp: error: copying member subobject of type 'std::atomic<bool>' invokes deleted constructor`

[barracuda156]

[ 50%] Building CXX object CMakeFiles/cubeb.dir/src/cubeb_log.cpp.o
/usr/bin/clang++ -DEXPORT="" -DFLOATING_POINT -DOUTSIDE_SPEEX -DRANDOM_PREFIX=speex -DUSE_AUDIOUNIT -I/opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_audio_cubeb/cubeb/work/cubeb-2bee6bcbd37b121ab197193fe466eef0e91b62b1/include -I/opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_audio_cubeb/cubeb/work/build/exports -I/opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_audio_cubeb/cubeb/work/cubeb-2bee6bcbd37b121ab197193fe466eef0e91b62b1/subprojects -pipe -Os -DNDEBUG -I/opt/local/include -stdlib=libc++ -Wall -Wextra -Wno-unused-parameter -fno-exceptions -fno-rtti -std=gnu++1z -arch x86_64 -mmacosx-version-min=10.11 -fvisibility=hidden -fvisibility-inlines-hidden -MD -MT CMakeFiles/cubeb.dir/src/cubeb_log.cpp.o -MF CMakeFiles/cubeb.dir/src/cubeb_log.cpp.o.d -o CMakeFiles/cubeb.dir/src/cubeb_log.cpp.o -c /opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_audio_cubeb/cubeb/work/cubeb-2bee6bcbd37b121ab197193fe466eef0e91b62b1/src/cubeb_log.cpp
/opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_audio_cubeb/cubeb/work/cubeb-2bee6bcbd37b121ab197193fe466eef0e91b62b1/src/cubeb_audio_dump.cpp:179:31: error: copying member subobject of type 'std::atomic<bool>' invokes deleted constructor
  std::atomic<bool> running = false;
                              ^~~~~
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/atomic:998:7: note: copy constructor of 'atomic<bool>' is implicitly deleted because base class '__atomic_base<bool>' has a deleted copy constructor
    : public __atomic_base<_Tp>
      ^
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/atomic:902:5: note: '__atomic_base' has been explicitly marked deleted here
    __atomic_base(const __atomic_base&) = delete;
    ^
/opt/local/var/macports/build/_opt_bblocal_var_buildworker_ports_build_ports_audio_cubeb/cubeb/work/cubeb-2bee6bcbd37b121ab197193fe466eef0e91b62b1/src/cubeb_audio_dump.cpp:179:21: warning: private field 'running' is not used [-Wunused-private-field]
  std::atomic<bool> running = false;
                    ^
1 warning and 1 error generated.

Build log: https://build.macports.org/builders/ports-10.11_x86_64-builder/builds/277858/steps/install-port/logs/stdio

Also: https://trac.macports.org/ticket/71027