I do not know where to even start, apologies for the noob question but seems there's nothing on this specific case in SO unless there's more generic terms I do not know.
Recent (like 5+ years or so), gperftools support environment variable that dumps used backtracing method. Set TCMALLOC_STACKTRACE_METHOD_VERBOSE to 1 and it'll show what it uses by default. You can also override used method via TCMALLOC_STACKTRACE_METHOD environment variable.
Another option is via package manager. On my debian system I see that libtcmalloc-minimal4 is linked without libunwind (as expected since it doesn't capture any backtraces), and libgoogle-perftool4 does depend in libunwind8. On debian and ubuntu you can see that by running apt-cache show .