EAGLE PCB How to set drill clearance?
Yes, this is done in the DRC settings.  One of the parameters sets how far traces must be from board edges, which includes the edges of unconnected holes.  I don't remember the exact setting name, but run "drc", look thru the settings, and you should be able to spot it.

Added:

You are saying you looked in the DRC but didn't find it.  It's actually quite obvious and one of only two setting under the "Distance" tab: