backtrace_top      71 src/eval.c     union specbinding *backtrace_top (void) EXTERNALLY_VISIBLE;
backtrace_top    1764 src/eval.c           union specbinding *pdl = backtrace_next (backtrace_top ());
backtrace_top    3797 src/eval.c       union specbinding *pdl = backtrace_top ();
backtrace_top    4206 src/eval.c       union specbinding *pdl = backtrace_top ();
backtrace_top    4224 src/eval.c       union specbinding *pdl = backtrace_top ();