http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59136
--- Comment #10 from Alexey Samsonov <samsonov at google dot com> --- Hi! Jakub suggested to use libbacktrace in libsanitizer. I've committed his patch to LLVM, and it will soon be merged into GCC, with many more changes. So, your change will not be needed. I've also ensured that, if you use llvm-symbolizer, it will not be started always, only when we actually need it to print a symbolized stack trace. Regarding "llvm-symbolizer: Unknown command line argument '--default-arch=x86_64'" failure: you see this because you don't use the trunk version of llvm-symbolizer binary. Sorry about that - we can keep ASan runtime in sync with LLVM head, but we surely get such dependency problems when we move it anywhere.
