The user has reported that tor breaks when timingsafe_memcmp(3) is missing, because it has only been added in 12.0 and backported to 11.1
with the patch multiple warnings generated, like:
./orconfig.h:521:5: warning: 'FreeBSD_version' is not defined, evaluates to 0 [-Wundef]
#if FreeBSD_version >= 1200000 // disabled: timingsafe_memcmp(3) has been added only in 12.0, and isn't yet available on older systems
3 warnings generated.
$ make -V PKGNAME
$ uname -r