Thank you for answer! All my constrains are the same as mentioned in the letter, my own compiled toolchain, fresh code, same gcc version/etc.
I found that if I do not separately compile kernel and directly compile my application using fresh system (which, as side effect, compile the sel4 kernel) - it fail in that way during ld library stage compilation. If, on the same binaries/environment/toolchain, I compile the kernel using the way mentioned in the letter
alex@tmp:~/genode/tmp$ make -C build/x86_64 KERNEL=sel4 kernel VERBOSE=
it works, and later I can compile without problems my application for sel4!
Seems that some problems are in genode build system, order of components build…
And, the problem is very exotic. I do separate file, generate clean C code after preprocessing - and compilation fail even by local gcc (not genode one!). I still can’t find a reason for a problem in code, probably environment could be wrong (suspect may be gcc run inappropriate gcc internal passes/tools? while I use the same binaries and env for successful compilation...)
Anyway, problem solved, thanks! Sincerely, Alex