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
even though it cannot work in there (a global "--import:libbacktrace"
flag may be applied to *.nims files, so we don't want the import to fail
in that case).
Ștefan Talpalaru
Zahary Karadjov