Remove trailing whitespace on save in IntelliJ IDEA 12

In 2020.1 IntelliJ version:

File -> Settings -> Editor -> General -> then scroll down to 'Save Files'

Don't know about 12, but there's the following setting in 13:

Settings → Editor → Strip trailing spaces on Save

As of IntelliJ 2017.2 it's under

Settings → Editor → General → Strip trailing spaces on Save