* Use an older glibc so resulting binaries can run
on older systems (without having to link statically
against glibc)
* Call packages static-compat-* to make it clear that
these packages are intended for compatibility with
older distributions
* Add further libraries to get static-compat-qt6-base
and some other static-compat-qt6-* packages building
* Adapt hacks to new config system
* Use distinct mkspec mingw-w64-g++ rather than
patching the existing win32-g++
* Testing QML and ANGLE is on TODO list
because it hasn't been tested since quite a time