Qt 6.2 development hosts

Requirements for Qt development hosts. New/updated platforms in bold.

• Windows 10 (64bit Intel: msvc2019, mingw81/gcc8.1)
  • Latest available Win10, optimally before FF
  • Cross complication toolchain changes (QTBUG-81947) <-- Postponed from 6.2 to 6.3.

• macOS Big Sur (11/10.16) (64bit Intel, 64bit ARM (QTBUG-87045): Xcode 12)
  • Supported versions 10.14, 10.15 and 11, if 12 is available by FF then the 10.14 will drop.
  • Also supported as host for Qt DC (QTBUG-81947)
  • Cross complication toolchain changes (QTBUG-81947) <-- Postponed from 6.2 to 6.3.

• Ubuntu 20.04 (64bit Intel: gcc9)
  • Cross complication toolchain changes (QTBUG-81947) <-- Postponed from 6.2 to 6.3.
  • Ubuntu 21.04 will be out, but we will stay on LTS 20-04

• Red Hat Enterprise Linux 8.2 (RHEL) (QTQAINFRA-4322 and QTQAINFRA-4323)
  • Use RHEL 8.4 if available in time, otherwise 8.2
  • CentOS is replaced by RedHat due to https://blog.centos.org/2020/12/future-is-centos-stream/
  • Cross complication toolchain changes (QTBUG-81947) <-- Postponed from 6.2 to 6.3.

• SLES 15 SP3 (64bit Intel: gcc10)
  • SLES (SUSE Linux Enterprise Server, small difference to SUSE desktop)
  • Open if (A) will work the same as in 6.0 & 6.1 (either update glibc OR build Qt for this host) OR we have ready made binaries working off the bat
  • Cross complication toolchain changes (QTBUG-81947) <-- Postponed from 6.2 to 6.3.

• openSUSE 15.3 (64bit Intel: gcc 9) (QTQAINFRA-4477)
  • openSUSE is KDE reference OS
  • Open if (A) will work the same as in 6.0 & 6.1 (either update glibc OR build Qt for this host) OR we have ready made binaries working off the bat
  • Cross complication toolchain changes (QTBUG-81947) <-- Postponed from 6.2 to 6.3.

• Debian packaging and repository support - Open and under planning
  • We are looking in to the Debian repository solution instead of Qt Online installer for Debian, thus this may be in a wrong place under this Epic. I.e. We are not planning to bring in Debian host OS support, instead we are investigating supporting Debian packaging and repositories from Qt for delivery and install and  maintenance on Debian based Linuxes (instead or on side with Online Installer).