Please use compat symbols to deny access to old symbols

Version 2.1.0 brought a soname bump for this reason:

** Two exposed functions are no longer exposed:
   _idn2_punycode_encode() and _idn2_punycode_decode() which were
   meant to be used internally only. The output needs additional
   checks to be used safely.
   This is the reason to for the SONAME bump, just in case.

This is overly disruptive. You could have turned the symbols into compat symbols instead, so that they are no longer available for linking.

Please consider reverting to the old soname. Thanks.