rpmbuild --rebuild   --define "dist .el8"  --define '_topdir /usr/src/redhat' --target=x86_64 --rcfile /tmp/tps_rpmrc_eXCvI9:/usr/lib/rpm/rpmrc:/usr/lib/rpm/redhat/rpmrc src/qpid-proton-0.28.0-1.el8.src.rpm
FAILED to rebuild src/qpid-proton-0.28.0-1.el8.src.rpm -- return code 256
REBUILD: FAIL for qpid-proton-0.28.0-1.el8.src.rpm
BUILDLOG: qpid-proton-0.28.0-1.el8.src.rpm-x86_64-rebuild.log contains full details.  Reports from make and rpmbuild, with line numbers:
6335-removing /tmp/tmpqu6qs2um.py
6336-running install_egg_info
6337-Writing /usr/src/redhat/BUILDROOT/qpid-proton-0.28.0-1.el8.x86_64/usr/lib64/python3.6/site-packages/python_qpid_proton-0.28.0-py3.6.egg-info
6338-+ chmod +x /usr/src/redhat/BUILDROOT/qpid-proton-0.28.0-1.el8.x86_64/usr/lib64/python3.6/site-packages/_cproton.so
6339-chmod: cannot access '/usr/src/redhat/BUILDROOT/qpid-proton-0.28.0-1.el8.x86_64/usr/lib64/python3.6/site-packages/_cproton.so': No such file or directory
6340:error: Bad exit status from /var/tmp/rpm-tmp.VbE0mi (%install)
6341-
6342-
6343-RPM build errors:
6344-    user mockbuild does not exist - using root
6345-    group mockbuild does not exist - using root
Last 20 lines of Build Log:
writing byte-compilation script '/tmp/tmpqu6qs2um.py'
/usr/libexec/platform-python /tmp/tmpqu6qs2um.py
removing /tmp/tmpqu6qs2um.py
running install_egg_info
Writing /usr/src/redhat/BUILDROOT/qpid-proton-0.28.0-1.el8.x86_64/usr/lib64/python3.6/site-packages/python_qpid_proton-0.28.0-py3.6.egg-info
+ chmod +x /usr/src/redhat/BUILDROOT/qpid-proton-0.28.0-1.el8.x86_64/usr/lib64/python3.6/site-packages/_cproton.so
chmod: cannot access '/usr/src/redhat/BUILDROOT/qpid-proton-0.28.0-1.el8.x86_64/usr/lib64/python3.6/site-packages/_cproton.so': No such file or directory
error: Bad exit status from /var/tmp/rpm-tmp.VbE0mi (%install)
RPM build errors:

DEPRECATION WARNING: python2 invoked with /usr/bin/python.
    Use /usr/bin/python3 or /usr/bin/python2
    /usr/bin/python will be removed or switched to Python 3 in the future.
    If you cannot make the switch now, please follow instructions at https://fedoraproject.org/wiki/Changes/Avoid_usr_bin_python_in_RPM_Build#Quick_Opt-Out

# ls /usr/src/redhat/BUILDROOT/qpid-proton-0.28.0-1.el8.x86_64/usr/lib64/python2.7/site-packages/proton/
_common.py       _condition.pyc   _delivery.pyo    _exceptions.py   _handlers.pyo    _io.pyo          reactor.pyc      _transport.pyc   _utils.pyc
_common.pyc      _condition.pyo   _endpoints.py    _exceptions.pyc  handlers.pyo     _message.py      _reactor.pyo     _transport.pyo   
[...]
# ls /usr/src/redhat/BUILDROOT/qpid-proton-0.28.0-1.el8.x86_64/usr/lib64/python3.6/site-packages/
_cproton.cpython-36m-x86_64-linux-gnu.so  cproton.py  proton  __pycache__  python_qpid_proton-0.28.0-py3.6.egg-info