+straddling of the proverbial fence causes problems. Here's an example
+of how things can go wrong. A locale can define a code point to be
+anything it wants. It could make 'A' into a control character, for example.
+But strings encoded in utf8 always have Unicode semantics, so an 'A' in
+such a string is always an uppercase letter, never a control, no matter
+what the locale says it should be.