Fix link version script

[BsAtHome]

Fix linking RT modules by not using binary fiddling but objdump and awk as described in #3413.

Also, allow master to compile on Buster (debian 11) using clang-16, which should have enough c++20 compatibility.

[andypugh]

If master now compiles on Buster, then I think there should also be a change to https://github.com/LinuxCNC/linuxcnc/blob/master/scripts/platform-is-supported

[BsAtHome]

But there is a snag... Buster will only properly work with clang-16^(*), which you need to install and you must configure accordingly. Buster's gcc will not work.

^(*) I think clang-13 will work, but I haven't tested it more than "it runs the tests".

[BsAtHome]

But there is a snag... Buster ...[snip]

That should read Bullseye (debian 11).

Buster (debian 10) is just too old and we need python >= 3.8 in master, which rules out Buster (debian 10).