sigaltstack support with kernel seL4

[Alexander Tormasov]

Do Genode (in particular, on seL4 kernel) support sigaltstack function?
I found its description in signal.h while it is unresolved during linking, and my search in libs did not give any results.
As I understand, it should be in libc?
I found it in depot/genodelabs/api/libc/2019-07-08/include/libc/signal.h
While no references to function body…