Resilient filesystems/raid/multiple backup points should be more than enough.
A word of caution on relying on backups without the other types of error prevention you mention: If it takes you a while to notice that bitrot has ruined a file, then it may have already propagated through your backups. The only type of backups that would account for this is archival backups, such as on tape or quality bluray discs.
I worked with a complier that would assume only compare the first 8 characters and would treat it the same afterwards.
Compiler copyright was around 1990.
Edit: This was for function names in C