This change breaks the build on FreeBSD:
libcacard/vscclient.c: In function 'send_msg':
libcacard/vscclient.c:111: warning: implicit declaration of function 'htonl'
libcacard/vscclient.c:111: warning: nested extern declaration of 'htonl'
libcacard/vscclient.c: In function 'on_host_init':
libcacard/vscclient.c:248: warning: implicit declaration of function 'ntohl'
libcacard/vscclient.c:248: warning: nested extern declaration of 'ntohl'
libcacard/vscclient.c: In function 'connect_to_qemu':
libcacard/vscclient.c:601: warning: implicit declaration of function 'socket'
libcacard/vscclient.c:601: warning: nested extern declaration of 'socket'