https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64999
--- Comment #12 from Ian Lance Taylor <ian at airs dot com> --- I should add that for purposes of Go, it's not all that important that libbacktrace does not yet handle sibling calls, because the Go compiler turns on -fno-optimize-sibling-calls by default (https://gcc.gnu.org/ml/gcc-patches/2014-10/msg01643.html in gcc/go/go-lang.c).
