libbacktrace bumped to the latest comit in the "master" branch of https://github.com/ianlancetaylor/libbacktrace
libunwind manually copied from https://github.com/llvm/llvm-project -
commit f749550cfe9f0bf2364abb2139835348587062ed - on top of which I
disabled a dependency on "../libcxx" that only makes sense in the LLVM
monorepo.
Allow separating stack unwinding and program counter collection from the
more expensive step of getting the associated debugging info for each
program counter.
This is useful for implementing efficient backtraces for exceptions - a
scenario in which you add a new backtrace each time an exception is
re-raised, but you rarely need to print them (usually when that
exception is uncaught).
libunwind snapshot - 673484b34189b1bccf73a2ec96968092bc8a26a7
Ștefan Talpalaru