Firstly, allow me to admit: I do not know for sure. There are few rules as arbitrary and obsessively enforced as the rules of grammar, but in this case, I use my reasoning as an English speaker.
A general rule is that hyphens link items and dashes separate items. Because of this, I lean to suggest use of the dash (-) in this instance, as the suffix referenced is going to be "linked" to different prefixes and other word anatomy.**
The em dash (—) It indicates a break in thought and can be used within a sentence to insert a parenthetical phrase, whereas the en dash (–) is used between ranges of numbers or dates, or between adjectival phrases containing two-word concepts. Thus, I do not believe either would be used in this case.
**This advices comes from the Official Glenn Friesen Style Guide, 1984—2014.