This commit is _exactly_ the result of

perl -i -pe 's/\bmemcmp\(/tor_memcmp\(/g' src/*/*.[ch]
perl -i -pe 's/\!\s*tor_memcmp\(/tor_memeq\(/g' src/*/*.[ch]
perl -i -pe 's/0\s*==\s*tor_memcmp\(/tor_memeq\(/g' src/*/*.[ch]
perl -i -pe 's/0\s*!=\s*tor_memcmp\(/tor_memneq\(/g' src/*/*.[ch]
git checkout src/common/di_ops.[ch]
git checkout src/or/test.c
git checkout src/common/test.h