Replace idnkit-1 support with idnkit-2 support (or drop it)
Currently, BIND doesn't compile with idnkit-2:
host.c:20:10: fatal error: 'idn/result.h' file not found #include <idn/result.h> ^~~~~~~~~~~~~~ dighost.c:30:10: fatal error: 'idn/result.h' file not found #include <idn/result.h> ^~~~~~~~~~~~~~ 1 error generated.
and for IDNA2008 support, we need to either add support for idnkit-2 or drop idnkit-1 support and leave only libidn2 support (!56 (closed)). The only reason why to keep idnkit-2 would be the licensing. idnkit-2 is licensed under custom JPRS BSD-like (with additional restrictions) license, and libidn2 is LGPL3+ (for our purposes) licensed.