"maybe_warn_former_built_in_variable" re-initialise on every call?

[Michael Goffioul]

While debugging some octave code, I noticed the
"maybe_warn_former_built_in_variable"
never assigns its static "initialized" to true, such that the
initialization is performed on
each call, that is on each assignment. That's probably not a big deal,
but there are a
couple of CPU cycles to gain over there :)

Michael.