Grammar: "allowing to" is not proper English

I'm not quite sure why, but I'm pretty sure it's not.  Rather, in
"allowing for foo" and "allowing to foo", "foo" modifies the sense in
which someting is allowed, rather than it being "foo" that's allowed.
"Allowing fooing" generally works, though it can sound a bit awkward.
"Allowing one to foo" (or "Allowing {him,her,it,Coq} to foo") is always
acceptable, in-as-much as it's ok to use "one".

I haven't touched the older instances of it in the CHANGES file.
Grammar: "avoiding to" isn't proper, either