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

contrib/wpa/src/drivers/driver_bsd.c

@@ -1800,9 +1800,19 @@ bsd_global_init(void *ctx)
 
 	global->sock = socket(PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
 	if (global->sock < 0) {
+	    if (errno == EAFNOSUPPORT) {
+		wpa_printf(MSG_INFO, "INET not supported, trying INET6...");
+		global->sock = socket(PF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, 0);
+		if (global->sock < 0) {
+		    wpa_printf(MSG_ERROR, "socket[PF_INET6,SOCK_DGRAM]: %s",
+			       strerror(errno));
+		    goto fail1;
+		}
+	    } else {
 		wpa_printf(MSG_ERROR, "socket[PF_INET,SOCK_DGRAM]: %s",
 			   strerror(errno));
 		goto fail1;
+	    }
 	}
 
 	global->route = socket(PF_ROUTE,