The current default for U.fontsdir is // (same directory as the blender executable). With this patch applied that folder will use an OS-supplied path for default instead.
This only changes it for Windows users, and does not have negative affect for other OSs. But does give a nice spot to add such OS-specific code in future if desired (a TODO comment is added there).
Obviously this does not do anything if users already have userprefs saved. So this only really applies to new users or when you "Load Factory Settings".