Ensure that ada host tools are built/linked with host g++ and thus linked
against the host glibc. Attempting to link against the target glibc leads
otherwise to linker errors like (since the host glibc has been updated to
2.38):
```
/usr/bin/ld: ../../libcommon.a(diagnostic.o): in function `get_terminal_width()':
/usr/include/stdlib.h:483:(.text+0x790): undefined reference to `__isoc23_strtol'
```
Not sure why GCC's build script is using the target "xg++" tool here. Maybe
a misconfiguration on my side or an upstream bug.
It wouldn't be possible to keep it nevertheless because then
we needed to add gcc-d to make dependencies which is not possible
because the regular package dropped it. It is also not possible
to build with the previous version of static-compat-gcc because
it would fail to find gmp and some other libs (using them from
the host system would be technically possible but one needed to
workaround linker errors with the C runtime).
For some reason also libobjc is missing but I suppose that's not
a bit loss.
* 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