libunwind is reentrant and signal safe, and works faster then then
gcc_eh (plus it has some custom patches for problems that have been
found during it's usage in ClickHouse).
gcc_eh may be missing in the system (if gcc was not installed), and
even if it exists clickhouse uses -nodefaultlibs, so some care should be
made to make it work.
Also this library is tiny and there shouln't be any problem to require
it always (there is already tendency to require some contrib libraries,
i.e. poco).
Signed-off-by: Azat Khuzhin <a.khuzhin@semrush.com>
Make ClickHouse compilable and runnable on risc-v 64
So far only basic functionality was tested (on real hw),
clickhouse server runs, exceptions works, client works,
simple tests works.
What doesn't work:
1. traces - they are always empty
2. system.stack_trace only have first frame
