utf8_to_string crippling

I don't think that's a good idea since I consider this a security related fix that potentially stops exploits against old code. That's also the reason why I've patched all pikes back to 7.4 to not accept non-shortest forms.

That is just not cool.

What perhaps could be added is compat goo for the Java special NUL encoding, to cope with that specific case. It's not a common delimiter in ASCII-based protocols. Still, it could conceivably be used as an exploit for C-based libraries, although I'd like to think that Pike isn't very susceptible to that.

I'd like to see the non-shortest version accepted per default and only only be filtered out if the I-might-decide-to-shoot-myself-in-the-foot-with-bad-string-handling-later flag is set.