Currently, there are a few bits of code in Wireshark that check, at compile time, whether INET6 is defined.
For Windows nmake builds, we appear to hard-wire INET6 to be defined; the user would have to edit config.nmake to turn it off.
For autotools builds, we go through a long series of tests for various flavors of IPv6 support.
For CMake builds, we appear to hard-wire INET6 to be defined.
Is there any reason to continue to try to handle OSes with no IPv6 support, or should we just get rid of the INET6 #define and unconditionally include the code that it currently controls?