pingtest fails to build on OpenBSD

FAILED: pingtest.p/test_pingtest.c.o
cc -Ipingtest.p -I. -I../libslirp-v4.7.0 -I../libslirp-v4.7.0/src -fcolor-diagnostics -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -std=gnu99 -O0 -O2 -pipe -MD -MQ pingtest.p/test_pingtest.c.o -MF pingtest.p/test_pingtest.c.o.d -o pingtest.p/test_pingtest.c.o -c ../libslirp-v4.7.0/test/pingtest.c
../libslirp-v4.7.0/test/pingtest.c:409:15: error: use of undeclared identifier 'AF_INET6'
    inet_pton(AF_INET6, "fec0::", &config.vprefix_addr6);
              ^
1 error generated.

pingtest fails to build on OpenBSD. AF_INET6 is in sys/socket.h