wpa_supplicant: Handle systems without INET (legacy IP) support
Currently, wpa_supplicant fails when legacy IP support is disabled
in FreeBSD (i.e., the world built with WITHOUT_INET and nooptions
INET in the kernel config). The proposed patch allows running
wpa_supplicant and connecting to wireless networks without INET
support when INET6 is available.
Reviewed by: cy, adrian, philip, roy_marples.name
Differential Revision: https://reviews.freebsd.org/D49959