GitLab

src/core/or/circuitlist.c:571:13: error: use of undeclared identifier 'tor_circuit'
  tor_trace(TR_SUBSYS(circuit), TR_EV(change_state), circ, circ->state, state);
            ^
./src/lib/trace/events.h:45:25: note: expanded from macro 'TR_SUBSYS'
#define TR_SUBSYS(name) tor_ ## name
                        ^
<scratch space>:130:1: note: expanded from here
tor_circuit
^
src/core/or/circuitlist.c:571:39: error: use of undeclared identifier 'change_state'
  tor_trace(TR_SUBSYS(circuit), TR_EV(change_state), circ, circ->state, state);
                                      ^
src/core/or/circuitbuild.c:503:3: warning: implicit declaration of function 'STAP_PROBEV' is invalid in C99 [-Wimplicit-function-declaration]
  tor_trace(TR_SUBSYS(circuit), TR_EV(establish), circ);
  ^
./src/lib/trace/events.h:53:5: src/core/or/circuitlist.c:1086:3: warning: implicit declaration of function 'STAP_PROBEV' is invalid in C99 [-Wimplicit-function-declaration]
  tor_trace(TR_SUBSYS(circuit), TR_EV(new_origin), circ);
  ^

                             ^

0.4.5.1-alpha on FreeBSD 12.2

Additionally, the file doc/HACKING/Tracing.md mentioned in the changelog https://gitweb.torproject.org/tor.git/tree/ChangeLog?h=tor-0.4.5.1-alpha doesn't exist.