Cannot build QT5 on macOS 11.0.1 Big Sur (with MacPorts) as the version information is mistaken.

[zhiyuanzhai]

The problem stops me from upgrading octave. Here's the output error message:

sudo port -v install qt5-qtbase
...
Sorry, "moc" cannot be run on this version of macOS. Qt requires macOS 11.0.0 or later, you have macOS 10.16.0.
Sorry, "moc" cannot be run on this version of macOS. Qt requires macOS 11.0.0 or later, you have macOS 10.16.0.
Sorry, "moc" cannot be run on this version of macOS. Qt requires macOS 11.0.0 or later, you have macOS 10.16.0.
make[2]: *** [.moc/moc_qvariantanimation.cpp] Error 1
make[2]: *** Waiting for unfinished jobs....
Sorry, "moc" cannot be run on this version of macOS. Qt requires macOS 11.0.0 or later, you have macOS 10.16.0.
make[2]: *** [.moc/moc_qabstractanimation.cpp] Error 1
make[2]: *** [.moc/moc_qabstractanimation_p.cpp] Error 1
make[2]: *** [.moc/moc_qpropertyanimation.cpp] Error 1
Sorry, "moc" cannot be run on this version of macOS. Qt requires macOS 11.0.0 or later, you have macOS 10.16.0.
make[2]: *** [.moc/moc_qanimationgroup.cpp] Error 1
Sorry, "moc" cannot be run on this version of macOS. Qt requires macOS 11.0.0 or later, you have macOS 10.16.0.
Sorry, "moc" cannot be run on this version of macOS. Qt requires macOS 11.0.0 or later, you have macOS 10.16.0.
make[2]: *** [.moc/moc_qsequentialanimationgroup.cpp] Error 1
make[2]: *** [.moc/moc_qparallelanimationgroup.cpp] Error 1
Sorry, "moc" cannot be run on this version of macOS. Qt requires macOS 11.0.0 or later, you have macOS 10.16.0.
make[2]: *** [.moc/moc_qpauseanimation.cpp] Error 1
Sorry, "moc" cannot be run on this version of macOS. Qt requires macOS 11.0.0 or later, you have macOS 10.16.0.
make[2]: *** [.moc/moc_qthread.cpp] Error 1
Sorry, "moc" cannot be run on this version of macOS. Qt requires macOS 11.0.0 or later, you have macOS 10.16.0.
make[2]: *** [.moc/moc_qthreadpool.cpp] Error 1
make[2]: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_pek.cn.rsync.macports.org_macports_release_tarballs_ports_aqua_qt5/qt5-qtbase/work/qtbase-everywhere-src-5.14.2/src/corelib'
make[1]: *** [sub-corelib-make_first] Error 2
make[1]: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_pek.cn.rsync.macports.org_macports_release_tarballs_ports_aqua_qt5/qt5-qtbase/work/qtbase-everywhere-src-5.14.2/src'
make: *** [sub-src-make_first] Error 2
make: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_pek.cn.rsync.macports.org_macports_release_tarballs_ports_aqua_qt5/qt5-qtbase/work/qtbase-everywhere-src-5.14.2'
Command failed:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_pek.cn.rsync.macports.org_macports_release_tarballs_ports_aqua_qt5/qt5-qtbase/work/qtbase-everywhere-src-5.14.2" && /usr/bin/make -j12 -w
Exit code: 2
Error: Failed to build qt5-qtbase: command execution failed
Error: See /opt/local/var/macports/logs/_opt_local_var_macports_sources_pek.cn.rsync.macports.org_macports_release_tarballs_ports_aqua_qt5/qt5-qtbase/main.log for details.
Error: Follow https://guide.macports.org/#project.tickets to report a bug.
Error: Processing of port qt5-qtbase failed

I have no idea why my stable version of macOS 11.0.1 is still considered as "10.16.0". Is there any explanation?

[JonB]

@zhiyuanzhai
I think there are various issues with Big Sur (if you search forum I think there are a few posts). I don't know whether this helps you, but https://bugreports.qt.io/browse/QTBUG-85546

Apple has confirmed that Big Sur will identify itself as both version 10.16 and 11.0 according to context.

[kuroki]

This is quite late but I had the same problem within a CI environment.

The solution is to export SYSTEM_VERSION_COMPAT=0

Hope this helps someone!